ANIMAL KINGDOM.

We embrace the earliest opportunity afforded by our alphabetical arrangement to present a few introductory observations in illustration of a science unrivalled in interest, and not greatly surpassed in importance by any department of human knowledge. Zoology, or the science which treats of the nature and history of animals (from ζωov, an animal, and aoyβς, a discourse), embraces so vast a field of observation, that although it cannot be regarded otherwise than as a single and beautifully connected science, its great extent of general doctrine, and multiplied variety of details, render necessary a subdivision into many branches, each of which, if worthily followed, is in truth more than sufficient to occupy the undivided attention of the most zealous votary. If in voluminous works exclusively devoted to natural history a single department of the science usually engrosses the entire attention of an author, it is evident that, in the present publication, it would not only be in vain to attempt a complete exposition of the subject under a single head, but that even the various treatises under which its different branches will be exhibited must be presented in a very abridged and compendious form. It shall be our endeavour, however, in the course of our natural history treatises, so to select and methodize the great leading facts of the science, as to enable our readers to form an accurate idea of the present state of zoological knowledge, even though certain minuter details, hitherto forming too conspicuous a feature of the subject, yet not essential to its truthful representation, should-in some measure be curtailed.

With a view to obviate to a certain extent the inconvenience arising from the disconnection of the different parts of ne science, which the nature of an alphabetic encyclopaedia necessarily occasions, we now propose, undei^the words iokm Kingdom, t to give, l¢ř, an exposition of suełi of the general doctrines of zoology as, not pertaining more to One department than another, may with the greater propriety be separated from the history of particular classes, and presented as a useful and appropriate introduction to the whole,—thus uniting the advantages of an alphabetical and systematic arrangement; 2dly, to present outlines of some of the prevailing systems of zoology, so as to exhibit in a condensed form the general principles of classification, and enable the student more clearly to understand the relative connections which exist between the scattered treatises in which the subjects (in their alphabetical order) will be afterwards more fully developed; and 2dly, to give a sketch of the arrangement to , be followed during the future progress of this work, which will not only serve as a guide Or general index to the separate articles, but will, on the completion of the Encyclopaedia, enable the attentive reader to methodize these articles in such a mariner as to form a complete and consistent system of zoology.

It iS by no means so easy as it may at first appear, to define precisely what is meant by the term animal, because, as we descend in the scale of beings, we find a transition sθ gradual from those whose powers and properties are strongly characterized, to others which, along with a scarcely perceptible share of sensation and voluntary motion, partake so greatly of the nature of plants, that themost acute naturalists have varied in opinion regarding the exact’ line of-their demarcation. There are also many plants which appear to differ less from certain animals than they do from other plants of an opposite nature’arid" construction.- This connected series of organized bodies, however, is riot graduated after the' mode established by some vague writers on natural history; [7:3:156]for it is not the most perfectly composed, but rather the ι least complex plants, which follow the most simply organized animals. It has been said that nature follows a continuous and ascending chain, from the mineral to the plant, and from the vegetable to the animal kingdom, the apex of which is crowned by the most perfect work of creation,—the human race. Certain minerals, such as amianthus or asbestos, no doubt exhibit a fibrous or woody structure; and coral, which has a stony texture, a vegetable form, and polypus inhabitants, has been adduced in illustration of the union of the three kingdoms.^[1. Virey, Moeurs et Iiiftinct des Animaux. ] But all such fanciful speculations are the result of partial and inaccurate observation. The calcareous basis of the coral is formed by a species of polypus, and has no more principle of increase in itself than the shell of the oyster or the waxen cells of the honey-bee. Its elegant branches are created by the instinctive labours of the animal inhabitants, which alone are possessed of life. The animal and vegetable kingdoms are more correctly compared to two great pyramids, intimately united at their bases, but diverging more and more as they ascend.

The extraordinary beings which by their ambiguous nature may be said to have thus blended two kingdoms into one, are called zoophytes or animal plants. They were arranged by Tournefort among vegetables, and were at an after-period removed to the class to which they really belong, chiefly on the authority and through the labours of Linnaeus and Pallas. These naturalists bore in mind what few of their predecessors seem to have remembered, that locomotion, that is to say, the movement of a body from place to place en masse, though a general characteristic, is not an essential or indispensable attribute, of animality; for numerous animals of the molluscous and radiated kinds are as permanently fixed to their native rocks and coral reefs as tho most deeply rooted plants are to the soil which gave them birth.

As sensation and the power of voluntary movement, in whole or in part, are the principal characteristics of animals, it is evident that the more these faculties become developed, the greater will be their removal from the vegetable kingdom. The more perfect the plant, and the more complicated the animal becomes, the greater disparity will be perceived to exist between them. If, in distinguishing the animal from the vegetable, nothing more were required than to point out the differences between an oak and an elephant, the line of demarcation would be easily drawn, and the characters of the respective classes could never more be confounded. But there are many plants which, though less aspiring than the oak, lay claim to a closer alliance to a higher kingdom; and many animals of a more carnivorous nature than the elephant are much more nearly connected by their nature and attributes with the vegetable tribes. When we perceive a living or animalized substance producing by suckers, buds, or offsets from its own body,—when we see that by the influence of light, air, and humidity, it is rendered capable of re-assuming the functions of vitality after a long period of suspended animation and apparent death,— when we ascertain that it cannot live except in water, or when saturated with moisture,—and that although it may be capable of certain languid and partial motions, it is yet fixed for life to a single point of space, where it derives its nourishment by means of external pores,—we have certainly the description of an animal of the lowest order, which applies at the same time almost equally well to vegetable life.

The following were the dicta of Linnaeus in relation to the three kingdoms of nature:—“Minerals grow; vegetables grow and live; animals grow, live, and feel.” The! only character common to these kingdoms, according tortile above definitions, is that of growth, or the power of adding to previous bulk. “The vegetation of stones,” it is observed by the late bishop of Llandaff, in his Chemical Essays, “ hath been admitted by many; and some have contended that minerals, as well as animals and vegetables, spring from seed, the greatest being nothing but the expansion of the parts of a minute grain of sand.” But mineral bodies in truth cannot be said to grow. They receive by aggregation or superposition, by mechanical or chemical agency, an increase of particles. Toumefort, indeed, was of opinion that stalactites in caves actually increased by an internal growth or propulsion like that of plants and animals. But it is known that these concretions add to their bulk by successive depositions of stony particles contained in the water which bathes their sides or percolates through the canal by which their centres are frequently perforated. They possess no attribute which bears the slightest affinity to that internal life which propels the fluids or assimilates the nutritive juices in the animal and vegetable kingdoms. Minerals, then, are destitute of that active power by which animals and plants effect an individual appropriation of such materials as conduce to their nourishment and increase, and which is carried on, not by casual juxtaposition, or the addition of similar particles previously prepared, but by an admirable and elaborate process, through which the ponderous bullock, with its immense load of fleshy fibre, converts into its own muscular and sanguiferous system the sweet-smelling grass of the meadow; and through which also the size and flavour of our most delicious fruits are often primarily derived, from an addition to their natural soil of substances of a very different and less inviting nature. Rome de Lisle has accurately observed that straight lines and plane surfaces are characteristic of mineral bodies, but that animals and plants are composed of curved lines or rounded surfaces, resulting from that central power of life which dilates the internal organs in all directions, and tends to produce spherical or cylindrical forms. The seeds of plants, the eggs of birds, and the young of all animals, are remarkable for the roundness of their outlines.

The objects of natural history, however, are not now divided into three kingdoms; for the characters which connect together plants and animals on the one hand, and distinguish both of these kingdoms from minerals on the other, are so obvious and strongly marked, that the divisions now established are those of organic and inorganic bodies; the former including all animals and plants, the latter all mineral substances. The definition of an animal, given by Μ. Virey, is as follows: A being, organized, sensible, endowed with voluntary motion, and provided with a central organ of digestion. And he thus defines a plant: A body, organized, insensible, not endowed with voluntary motion, nourished by external pores. To these he adds another character, that the reproductive organs of plants are developed and thrown off every year, whereas those of animals are persistent. It is evident that the last clause of his first definition—that which relates to the central organ of digestion—if rigorously applied, would exclude almost the entire of the infusoria from the animal kingdom.

Perhaps the most efficient mode of distinguishing between aňimals and plants is by haying recourse to a certain range of characters, derived from the study of then [7:3:157].internal structure and organic functions: thus the possession of nerves, muscles, and a stomach, with the consequent attributes of sensation, voluntary motion, and digestion, will be found to separate animals properly so called from all other organized matter. If these leading characters are not common to all animals, they are at least proper to them alone; and if the whole of these characters are not always united in the same animal, we invariably find at least one of the three. Thus certain species of polypus, the sensibility and voluntary movements of which cannot be said decidedly to manifest themselves, are obviously furnished with a digestive cavity ar stomach; and many of the infusory animals, of the digestion of which we know nothing, are as perfect in regard to their varied powers of locomotion as any of the aigher classes. Numerous zoophytical species, indeed, are af so simple a nature, that in them we cannot perceive either a distinct tissue or a nourishing fluid; but we can brm some opinion of the nature of their elements from the character of their properties. Irritability indicates serves, motion supposes the existence of muscles, and he continued maintenance of life attests nutrition. Thus ihe materials of animal life, so vaguely constituted in [hese creatures, are detected by their general properties.

In relation to their chemical characters, animals may be said to be principally composed of azote; and vegetables, vith the exception of cruciferae, of carbon. Animals ab- ,orb oxygen, plants disengage it; the former reject car- )on, the latter become impregnated with it. An exchange )f principles is thus effected between the two great divisions of organized existence; but it has been observed hat plants merely fix or organize carbon, whereas animals ιppear to transform into azote, both the air which they , espire, and the aliments by which they are nourished.

It has been asserted that a single mouth, or opening to he digestive canal, sufficiently characterizes animals from >lants, as the latter always possess innumerable pores, vhieh with them are the representatives of the mouth, ιnd conduce to the same ends; but this distinction is in 'act inaccurate, as some species of Fasciola possess two Rouths, certain Tristomae three, and the genus called by >uvier Rhisostoma many more; to say nothing of the in-üsorial tribes, most of which have no mouth at all, but lerive their nourishment by imbibition through the melium of external pores. Nutrition, or the power of deliving nourishment from other bodies, is common alike to plants and animals, and effects for organized and living )odies that increase of bulk which inorganic or disorgan-zed substances can only attain through the medium of an clinity of particles, or by mechanical aggregation. The unctions of nutrition, however, as manifested in the ani-nal and vegetable kingdoms, are very differently perform'd in each. Fixed for ever to the soil which gave them nrth, plants are rendered incapable of· searching after nourishment by a voluntary change of place, but derive heir chief support from roots, the pores of which absorb he nutritive portions from the humid soil, and by a uniform and continuous action, which is only interrupted by I in absence of the necessary moisture. The generality of mimais,on the contrary, being possessed of the power of oeomotion, are also endowed with the capacity of transiting w ith themselves a supply of necessary nourish-nent; for which purpose they are provided with an in-ernal cavity or stomach, the inward surfaces of which ire provided with absorbing pores, which Boerhaavĉ excessively named internal roots. “The magnitude of this < lvι ty, observes Cuvier, '∙ i in a number of animals, per-jnits them to introduce solid substances into it. It was necessary then that they should have instruments for dividing those substances, and liquors for dissolving them. In a word, with such animals nutrition does not icnmedi-ately commence upon the absorption of the substances which the soil or the atmosphere furnishes. It is necessarily preceded by a vast number of preparatory operations, the whole of which constitute digestion.” ^[2. Lectures on Comparative Anatomy, lecture i. ] The motion of the nutritive fluid in plants, from the simplicity of their structure, and the fixity of their position, seems to be preserved by simple external agents. “It appears to proceed upwards by the effect of their spongy or capillary texture; and the evaporation which takes place at their top, and its motion in that direction, is the more rapid in proportion as the evaporation is great. It appears also that the motion of this fluid may even become retrograde, when it ceases to flow in its usual course, or changes into absorption by the coldness and humidity of the atmosphere.”^[3. Ilàă. ] In regard to animals, however, the case is different. Being destined continually to change their localities, and to live exposed to a variety of temperatures, they require an active principle within themselves for the conveyance of their nourishing fluid. This fluid is therefore contained in a multiplicity of canals, which are ramified from two trunks, communicating with each other in such a manner that the roots of the one, called the venoüs system, receive the contents which the other, known as the arterial system, has propelled to the extremity of its branches, and restore them to the centre, from which they are again driven forward. It is this rotation· which constitutes what is called the circulation of the blood. It may be regarded as a function of a secondary order proper to animals, but not universal to that kingdom, as it depends in a great measure on the existence of that central organ called the heart, of which some classes are entirely destitute. It is therefore less essential to life than digestion, and not so intimately related to the faculties of sensation and locomotion. In regard to respiration, animals which are unprovided with a regular circulating system respire, like vegetables, over the whole of their surface, or by various vessels which are placed at different points, and convey the air to the interior of their bodies. “No animals,” says Cuvier, “respire by a particular organ, except such as have a real circulation; because in them the blood coming from one common source, the heart, to which it constantly returns, the vessels that contain it are so disposed that it cannot arrive at the other parts until it has passed through the lungs. This, however, cannot take place in vegetables, or in those animals in which this fluid is everywhere diffused in a uniform manner, without being contained in vessels.” Pulmonary or branchial respiration is therefore an animal function of a third order, invariably connected with circulation, and one degree removed from such faculties as are essential to animal life.

When a vegetable dies of old age, it begins to decay in the centre. We frequently see ancient willow-trees entirely dead, except in a few slender twigs, or in small portions of their superficial bark. An animal, on the contrary, first dies in its extremities and circumference, whilst the heart or central portion continues for a time to perform, however languidly, its accustomed actions.

Among plants both sexes usually occur in the same individual, or even on the same flower; but in a far greater proportion of animals the two sexes are represented by separate individuals. There is indeed no genuine hermaphrodital union among mammiferous animals, birds, reptiles, fishes, cuttle-fish, Crustacea, or insects[7:3:158]. Among many molluscous animals, however, such as the oyster and other bivalves, both sexes are found on the same individual, which is consequently sufficient of itself for the purposes of reproduction, and may be regarded as a genuine hermaphrodite. This singular order of things is in fact indispensable to the nature of bivalve testacea, which, being almost entirely deprived of the power of locomotion, and destitute of eyes or other organs by which to distinguish each other, require to possess within themselves the power of reproduction, lest their kind should cease. The species is both represented and continued by a single individual. In the earthworm, again, the same union of the sexes occurs, but modified in such a way that the concurrence of two individuals is required for the continuance of the race, and each acts in relation to the other both as male and female. This is also the case with slugs, and a great proportion of univalve and turbinated shells. Lastly, the zoophytical animals are not distinguished by any sex, but are multiplied by separation or excision of parts of their own bodies.

The law which establishes a perfect distinction and separation of the sexes in animals seems likewise to produce a double and symmetrical structure, and is of great extent in that kingdom; whilst the circular or radiated form more especially distinguishes plants, and is also characteristic of those zoophytical tribes which, both by name and nature, claim an alliance to the vegetable world.

The grain, and the fruit or kernel, may be said to bear the same relation to a vegetable as the egg or the embryo does to an animal,—with this difference to be borne in mind, that the concurrence of the sexes is necessary to the formation of the vegetable egg, whereas in the animal kingdom that circumstance is indispensable only to the fecundation of the pre-existing germ. The perfection of a plant, and the ultimate aim of its existence, if we may use such a phrase to an inanimate structure, consist in the continuance of its kind. In such as are named annuals especially, the term of whose existence is limited in many instances to a small portion of the year, the ripening of the seeds is speedily effected, and, after a very brief period, death succeeds “the bright consummate flower.” In numerous tribes of insects the same fleeting existence is observable, though the ephemeral nature of these last-named tribes is rather apparent than real, as the wonderful metamorphoses to which they are subjected conceal their identity from the eye of the uninitiated, and greatly interfere with a continuous tracing of the same individual from the egg to the perfect form. For example, many aquatic flies, such as the Ephemerae and others, whose declared and more obvious existence does not exceed a few hours, have, previous to their assuming the winged state, spent months or even years in the banks of rivers, and beneath the surface of the stream.

Even the mode of reproduction among the lower tribes of the animal kingdom bears some analogy to that of vegetables; and as the vital principle in the smallest branch or portion of a willow-tree is easily continued and increased though separated from the parent stem, so in many zoophytical animals a bud, branch, or other section, removed from the full-grown individual, suffers no injury from such partition, but, on the contrary, acquires almost immediately a complete and independent power of existence within itself, and is ere long capable of exercising or enduring a. like division in favour of posterity, ι Animals as .well as plants are liable to be-affected by the revolutions of the seasons; for the period of flowering in the one class is answered by the season of love in the other, and the fall of the leaf is only analogous to the periodical renewal of the feathers of birds and the hair of quadrupeds. The platanus quits and renews its superficial bark, while serpents and cray-fish cast off and reproduce their sealyand crustaceous covering. To be produced and nourished, to increase, to engender, and to die, are characters common to every class of organized existence; but animals properly so called are alone endowed with instinct and voluntary motion,—they alone possess nerves, muscles, digestive organs, and blood, with the faculties of perception, &c. consequent on these attributes.

The preceding observations will serve to illustrate the principal relations and analogies which exist between animal and vegetable life. But there are other characters proper to animals, the whole of which, however, are not universally bestowed on that class, of which it will now be proper to say a few words. The substance of which even the most perfect animal is composed may be resolved into four tissues, — the cellular, the muscular, the fibrous, and the medullary.

The cellular tissue is the most extensively bestowed, and forms, according to an expression of the French physiologists, the canvass of all the organs, and of every animal. It is even common to vegetables, and serves at once to compose, to unite, and to separate the organs. Formed of laminae or plates interlacing each other in every direction, and perforated by small cavities which have intimate communication, it also sometimes presents itself under the form of membranes, which, when they assume a tunnelled or cylindrical shape, are denominated vessels. It is in this tissue that the gelatine accumulates for the formation of the cartilages, and the calcareous salts for that of the bones. It is amongst its meshes that the fat is amassed, the small vessels distributed, and warmth developed. It forms the basis of the organs.

The muscular tissue is composed of fibrin, and its chief property is that of contraction. It forms what are called the fleshy parts of bodies. Bundles of this tissue crossing each other compose the heart, and, under another aspect, form the stomach and intestines. It is the agent of movement.

The medullary or nervous substance is conrposed of a soft albuminous pulp, and is protected by powerful membranes. It enjoys the admirable faculties of perceiving, comparing, judging, remembering, and willing; it gives to the senses their special properties, to the muscles their moving force, and is the seat of that mysterious union between mind and body through which the intellectual faculties result or become manifested, and the exact nature of which the most acute of metaphysical inquirers, and the most accurate and thoughtful observers of nature, have as yet sought in vain to illustrate. Sensation is the attribute of the nerves.

The fibrous tissue, the most resistant and unfeeling of all, fastens the bones to each other, and connects the bones and the muscles. It forms the ligaments, the tendons, many vessels, and some resisting membranes employed for the protection of the more important organs. In composition it approaches the cellular tissue, but its properties are dissimilar. Its character is resistance.

Each of these tissues is destined to the performance of a special purpose: The cellular organizes, the muscular moves, the nervous perceives, the fibrous attaches and resists; but one and all are under the influence of that nourishing fluid, so different in various animals, known by the name of blood. This fluid is red, circulating, of a high temperature, in animals of the superior classes—that is, the mammalia and birds; less red; colder, and not so charged with oxygen, in fishes and reptiles; colourless, but still circulating, in the mollusea without either colour or movement in insects; scarcely perceptible in certain worms; and apparently wanting in zoophytes. It is this fluid which animates all the organs, and presides over [7:3:159]every function. Nutrition exhausts its principles, digestion repairs them, respiration elaborates and renders it perfect, and the action of the heart gives it circulation.

All these elements united and variously combined compose the different organs of animated beings, the harmonious action of which organs forms the essence of our wellbeing, physically considered, in the present stage of our existence. The human race possesses the attributes of animal life in common with the brute creation; but we must ever bear about with us a firm conviction that these are “the accidents, not the essentials of our nature;”^[4. Grinfiel<1 ’ 8 Letters to Laurence. ] and that however proper it may be to mention them as the technical statements of physiology, yet that they are totally inadequate to the description of a being who bears about with him the germ of immortal life, and knows that he was created “but a little lower than the angels.” “Those persons,” says Buffon, “who see, hear, or smell imperfectly, are of no less intellectual capacity than others; an evident proof that in man there is something more than an internal sense. This is the soul of man, which is an independent and superior sense, a lofty and spiritual existence, entirely different in its essence and action from the nature of the external senses.”

It is easy to perceive that one set of organs may be so related to another as constantly to require its eo-existence. Thus, circumscribed respiratory organs are always accompanied by a heart, which causes the blood to flow through them; and a brain is never found without nerves αd muscles, which serve it as faithful ministers and attendants. The brain receives impressions, and is enabled to judge of them through the medium of nervous sensations: this is the first mode of the functions of relation. But the order is inverse so far as relates to the phenomena of the will as connected with the exercise of the voice and the organs of movement. The brain wills or commands, the nerves transmit the order, and the muscles execute it.

There are other eo-existences in the animal economy as apparent as those above alluded to, the motives of which are not, however, so easily comprehended. We are still ignorant why the viscus called the liver should always exist where there is a heart; and why all orthopterous insects should have the forehead furnished with a broad plate.

It will readily be conceived that the diversified circumstances of life in the various tribes of animals necessitate an infinite variety of phenomena in their functions and faculties. An animal which respires, and has its dwelling in the waters, can neither feel nor move after the manner of one which breathes in the pure air; and wherever there are branchiae or gills instead of lungs, we are sure also to find oviparous generation, an incomplete circulation, absence of voice, and imperfect organs of hearing and smell. But the existence of lungs alters the relation of the whole of these functions.

The same principle, may be applied to the different kinds of aliment. A carnivorous animal is endowed with force and courage: it has a strait stomach, short intestines, and a lank or somewhat slender form. Herbivorous animals, on the contrary, are usually mild and timid, dull in action, of a sluggish nature, and unapt to self-defence: their intestines are spacious, and their external forms more or less massive. “The disposition of the alimentary canal determines, in a manner, perfectly absolute, the kind of food by which the animal is nourished; but if the animal did not possess,in its senses and organs of motion, the means, of distinguishing the kinds of aliment suited to its nature, it is obvious that it could not exist. An animal, therefore, which can only digest flesh, must, to preserve its species, have the power of discovering its prey, of pursuing it, of seizing it, of overcoming it, and of tearing it in pieces. It is necessary then that this animal should have a penetrating eye, a quick smell, a swift motion, address and strength in the jaws and talons. Agreeably to this necessity, a sharp tooth, fitted for cutting flesh, is never co-existent in the same species with a hoof covered with horn, which can only support the animal, but with which it cannot grasp any thing: hence the law according to which all hoofed animals are herbivorous, and also those still more detailed laws, which are but corollaries of the first, that hoofs indicate molar teeth with flat crowns, a very long alimentary canal, a capacious or multiplied stomach, and several other relations of the same kind.”^[5. Lectures on Comparative Anatomy, vol. i. p. 56. ] In short, such harmony exists between the different organs, according to the leading forms after which they are modelled, that an experienced anatomist, from an inspection of a very limited portion of a body, can form an accurate opinion regarding the entire characters of an animal. It is thus that Cuvier, combining profound knowledge of detail with a commanding power of generalization, has, as it were, called back into existence those long-extinguished races whose scattered and imperfect remains attest the wonderful revolutions to which our planet has of old been subjected.

The aid which natural history has derived from the sister sciences of anatomy and physiology, is in nothing more apparent than in the improved systems of modern classification. It was formerly the practice to adopt, as the basis of arrangement, the modifications of some single organ, chosen arbitrarily and at hazard. Of course it did not follow that all the other organs would resemble each other in all the animals in which the likeness of this one organ might be preserved. Nothing, therefore, could be affirmed respecting the other organs belonging to the whole of a class or genus of animals, which we should have attempted to distinguish by characters taken from this unimportant organ. “Suppose, for example,” says Cuvier, “that we had made three divisions of animals, the aerial, terrestrial, and aquatic, as they were anciently classed; there would be included in the first class, besides what are commonly called birds, some mammiferous animals, such as bats—some reptiles, as the dragon—some fishes, as the flying fish—and an infinite multitude of insects. Similar difficulties would occur, in a greater or less degree, in the other two classes.” “This example is well calculated to show how important it is that the characters of our divisions should be well chosen; for, though in the formation of methods and systems of natural history, errors so flagrant as the above are not now committed, several naturalists, even in modern times, have adopted di-, visions which, in the detail, tend to similar results.”^[6. Loe. cit. p. 62. ]

It is both interesting and important to trace the different systems of organs in the animal kingdom, from their first feeble rudiments, through a gradual and longcontinued chain of increasing manifestation, to their complete development in some particular class or order, in which the perfect exercise of a special function is indispensable to its wellbeing. It is in accordance with such development that the improved classifications'of recent times have been established; and it is now admitted as an axiom, that a natural and philosophical arrangement of animals can have no other foundation than a knowledge more or less perfect of anatomical structure. It does not follow from this that every naturalist must be a profound [7:3:160]anatomist; for such is the multiplicity of details connected with the history of the haunts and habits of species, and with the discrimination and description of their external characters, which in truth form the proper object of the zoological inquirer, that a much longer period than that allotted to the life of man would be required likewise to ascertain the distinctions of internal structure, were it necessary to apply anatomical science to all the minor details, or even to the less important divisions, of natural history. But the beauty and excellence of the anatomical system consists in the admirable co-ordination of characters which it exhibits, and through which, with rare exceptions, we are able to arrange the subjects of investigation in a natural manner, even according to their external aspect, as soon as we have established certain great leading principles of classification drawn from the facts of anatomical science. The more essential and important characters even of internal structure are manifested externally by the influence which they exert over more obvious though less dominating attributes; and thus, even in the absence of a positive and direct knowledge of general laws, these are indicated with wonderful certainty, though somewhat empirically, by means of superficial observation. It is thus that, through the combined efforts of the naturalist and anatomist, the convenience and facility of application which characterize artificial systems, and constitute indeed their sole value, may be combined with that philosophical accuracy and consonance with the march of nature which results from deeper and more substantial views.

The object of every good method, according to Cuvier, is to reduce a science to its simplest terms, by reducing the propositions it comprehends to the greatest degree of generality of which they are susceptible. A good system must therefore be such as will enable us to assign to each class, and to each of its subdivisions, some qualities common to the greater part of the organs. This object is to be attained by two different means, which may serve to prove or verify one another. “The first, and that to which all men will naturally have recourse, is to proceed from the observation of species to uniting them in genera, and to collecting them into a superior order, according as we find ourselves conducted to that classification by a view of the whole of their attributes. The second, and that which the greater part of modern naturalists have employed, is to fix beforehand upon certain bases of division agreeably t¢ which beings, when observed, are arranged in their proper places. The first method cannot mislead us, but it is applicable only to those beings of which we have a perfect knowledge; the second is more generally practised, but it is subject to error. When the bases that have been adopted remain consistent with the combinations which observation discovers, and when the same foundations are again pointed out by the results deduced from observation, the two means are then in unison, and we may be certain that the method is good.”

The true distinction between the value of an artificial and of a natural method in zoology consists in this, that the former teaches us little more than the name of an animal, whereas, in relation to the other, we have no sooner ascertained the name of a species, or its position in the System, than we become at the same time acquainted with numerous facts in its character and history, which we never could have discovered, except by actual observation, had it formed part of those miscellaneous and falsely connected groups which so often constitute the divisions of an artificial system. A natural arrangement is also of great advantage in facilitating general views, by rendering a single animal a type or representative of many, as containing in itself the essential characters of a numerous' tribe; and thus the whole animal kingdom may be represented by a few hundred species. By a too strict adhe∙ rence, however, to the natural method, we are apt to lose the advantage of precision in individual definitions, and, in the case of the numerous transitions, find ourselves unable to fix any limits, if these have not been already es∙ tablished by nature. To discover a medium between these two methods, so as to unite the advantages of each, is now more than ever desirable in the formation of systems.^[7. See Cal∙us’s Introduction to Comp. Anat. translated by Gore. ' ] He indeed who flatters himself with the idea that the families, tribes, genera, and Sections, which he has laid down on paper, are so many natural divisions, can only be compared to the person who, because he may find the meridians and other circles of an armillary sphere convenient for the division of the heavens, should therefore imagine that they must exist in nature. “In one and the other case,” Mr Macleay observes, “artificial modes of distribution are resorted to, which, however ingenious in themselves, are but sad proofs of the limited state of our faculties, when we consider, that without such instruments the vastness and sublimity of the creation cannot be comprehended.” (Ilorae Entom.) There is in fact no such thing as classification in nature. In the animal as well as in the vegetable kingdom certain species are grouped together by such analogies of form and structure, as to render their mutual resemblances apparent even to an ordinary observer. To these groups the name of natural families may, without impropriety, be applied; but that no general system of arrangement exists in nature, by which the various genera may be made to follow each other, like the links of a linear chain, is evident from the discordant, ever-varying, and frequently arbitrary methods employed even by the most accomplished naturalists of the day. We must probably rest satisfied with such a system as presents the objects of natural history in conveniently arranged groups, the component parts of each of which bear a considerable resemblance to each other, without seeking after what is unattainable, namely, the establishment among these groups of a perfectly natural and well-graduated sequence. “When there are,” says Mr Vigors, “no absolute divisions except species in nature—and this, from every observation I have been enabled to make, I firmly believe to be the case—every division which we are forced to institute in our arrangements for the convenience of illustration, and indeed for the purpose of mutual communication with those who are engaged in similar researches with ourselves, must be to a certain extent arbitrary and artificial; and every inquirer into nature may cause the line of demarcation that separates his conterminous groups to infringe more or less on the limits of either, according to his peculiar mode of viewing his subject·”^[8. Linnoean Transactions, vol. xiv. p. S12- ]

No satisfactory argument can be adduced to prove, as some have imagined, that the specific differences of animals have resulted from the lapse of time, and the effects of climate, or other secondary causes. The variation ol specific character, though sometimes remarkable, is re-stricted; and Cuvier has shown, from a minute examina tion and comparison of mummies of the ancient Egypt> ar Ibis with individuals of the modern race, that in regan to that species no perceptible change has taken place du ring the last three or four thousand years. * The origins creation of distinct and predetermined species is the ra tional and well-founded belief of all who have studied th«
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subject with attention, unbiassed by any prejudice in favour of imaginative views, which have no foundation in the facts of nature. “It is certain by revelation,” says Buffon, “that all creatures have equally participated in the favours of creation; that the first two of each species were formed by the hands of the Creator; and we ought to believe that they were then nearly such as they appear at present in their descendants. We must also consider, that although nature proceeds by gradual, and frequently by imperceptible degrees, the intervals are not always the same. The more exalted the species, the fewer they are in number; and the shades by which they are separated are more conspicuous. The smaller species, on the contrary, are very numerous, and have more affinity to each other, so that we are the more tempted to confound them together in the same family. But we should not forget that these families are our own works; that we have made them for the ease of our memories; and that if we cannot comprehend the real relations of all beings, it is ourselves, not nature, that are in fault; for she in truth knows not our pretended families, and recognises individuals alone.”

Omnipotence, the first, the greatest, and indeed the ļonly truly creative power, formed the species of animals; and the influence of man and of physical agents has produced the varieties. But it is only superficial characters which either the one or the other of these ulterior causes has the power of modifying. The basis of organization, or real specific mould, remains unalterable, though a thousand circumstances constantly tend to produce variations in the external forms. Of these circumstances the most powerful is no doubt climate; under which name it is necessary to comprehend the differences of local situation and temperature, the nature of the soil and its productions. It is climate, in the first place, which chiefly determines the geographical position of animals, and thus commences the action of the modifying powers. The nature of their food is also highly influential; and as it depends so immediately on the qualities of temperature and soil, the climate is still the modifying cause. If the same animals usually accompany the same vegetables, it is because the constitution of both demands similar influences, and because through each other they are both dependent upon the same support. Certain animals are leagued with certain plants, and these again with certain soils and cliquâtes; and a careful observance of these mutual dependencies exhibits one of the finest and most beautiful harmonies of nature. This, however, is not the place in which to discuss the intricate and important subject of the geographical distribution of animals.

Certain original forms have been continued since the creation of organized beings, and all the individuals which represent or belong to one of these forms constitute what is called a species. The slighter differences which occasionally prevail among the individuals themselves, independent of the customary distinctions of age and sex, are called varieties. Such varieties are seldom permanent, and are usually lost by the progeny re-assuming the ordinary and characteristic form or colour, except in some remarkable instances, such as the horse, dog, and other long-domesticated species, of which man has so thoroughly altered the original condition, as to have impressed them with a second and more pliant nature. An individual, according to Buffon, is a separate detached being, and has nothing in common with other beings, excepting that it resembles, or rather differs from them. All similar individuals which exist on the earth are considered as composing the species of those individuals. Yet it is neither the number nor collection of similar individuals which constitutes them; for a being which existed for ever would not be a species. “Species then is an abstract and general term, the meaning of which can only be determined by considering nature in the succession of time, and in the constant destruction and renewal of beings;” and it is by comparing the present state of nature with the past, and actual individuals with their predecessors in kind, that we come to attain a clear idea of what is called species; for a comparison of the number or resemblance of individuals is only an accessory idea, and frequently independent of the first. The ass resembles the horse more than the barbet the greyhound; yet the latter are but one species, since they produce a fertile progeny; but the horse and the ass are certainly of different species, “since they produce together vicious and unfertile young.”

It is indeed difficult to define the term species, otherwise than as an assemblage of individuals descended from common parents, which bear as great a resemblance to them as they do to each other. Species then are distinguished by fixed forms, which, though to a certain extent alterable, and for a limited time, by external or accidental causes, are yet handed down unimpaired from generation to generation; and although certain species seem to have disappeared entirely from the earth, in consequence of the great natural catastrophes which have taken place in ancient times, and the local distribution of many still existing races has been modified or changed by the influence of man no less than by the accidents of nature, there is no reason to believe that any one species has sprung from the gradual alteration of another, or that the circumstances, under which an individual may have been at first casually placed were sufficient to develope both form and function, without an impress from a higher and more powerful hand, by which it was fitted to perform its part (pre-ordained) in the great theatre of the world.

Animals which by their union produce fertile individuals, arc generally reputed of the same species. This law of nature, as it was formerly called, having been found to admit of certain though rare exceptions, is not now so broadly insisted on as a test of specific identity as it was in preceding times. But it appears, from the result of numerous experiments, that the generality of animals produced from a cross between even the most nearly allied species, are either altogether incapable of reproduction, or fertile in so imperfect a degree, that their descendants speedily become entirely sterile. It has been said that birds alone were unsubjected to this rule, and that hence has arisen the wonderful variety which that beautiful class exhibits. There is no doubt of the occasional fertility of their hybrids, as in the case of those mule birds produced between the goldfinch and canary; but as it has not been proved that such unions of distinct kinds ever take place when uncontrolled by the depraving influence of domestication, there is no reason to attribute the origin of any of those species or varieties which are known to exist in a wild state to any such improbable alliance.

It is known that a productive union may take place between animals of a different species, provided such species belong to what naturalists call the same natural family. Thus the ass and the mare, or the horse and the female ass, produce the well-known animals called mules: the zebra also produces both with the horse and the ass; but in order to deceive the female zebra, it is said to be necessary to paint the hides of the former with those bizarre colours which adorn her accustomed mate.^[9. Dict. Class. d’Hist. Nat. tome i. p. 48. ] It is probable, [7:3:162]however, that all these unions are so far forced and unnatural, that they never take place except through the influence ' of man, when domestication, and the numerous changes consequent upon it, have altered or impaired their natural instincts; for it has been observed that, however education may perfect certain special qualities, which man has the art to render subservient to his own convenience, yet a more extended view of the effects of domestication will convince us, that it is almost always to the disadvantage of their natural capacities that the brute creation are made to borrow the mask of human intelligence.

Buffon appears to have adopted from Ray a rule which many now regard as inaccurate and artificial, but which he made use of to determine the identity of animal species, viz. “any two animals that can procreate together, and whose issue can also procreate, are specifically the same.” In this, however, it has been observed that he contradicts himself by afterwards admitting that the sheep and goat are of different species, at the same time that he asserts that the he-goat and the ewe produce a mixed breed which continue fertile for ever. Dr John Hunter (a great authority) was also of opinion that the true distinction between different species of animals must ultimately be gathered from their incapacity of propagating with each other an offspring capable of again continuing the kind. Thus the horse and ass beget a mule capable of copulation, but incapable of begetting or producing offspring. The accident of a mule breeding, according to the same authority, even if it were proved, would only show that as many perfect animals of true species and distinct sexes are incapable of breeding at all,—(thus showing that nature, even in her greatest perfection, sometimes deviates ’ from general principles),—so it may occasionally happen that a mule shall breed from the circumstance of its being “a monster respecting mules.”

The doctrine of equivocal generation has received no support from any recent investigations. All that is known decidedly leads to the opposite conclusion; and if certain mysterious or unaccountable phenomena have perplexed the physiologist, the only legitimate deduction is, that he has met with something which he cannot comprehend; for those aberrations (if such they really are) from the usual laws of nature are not so much exceptions to the general rule, as additional instances of effects in nature, the regulating causes of which we are as yet incapable of demonstrating. The rules of philosophizing lead us to reject the admission of more causes than are sufficient for the explanation of phenomena; and if, for example, mites, and “such small deer,” derived their origin solely from the caseous and other substances in which they are generally found, the sexual distinctions which prevail among other animals would in them be unnecessary, and would not therefore be observable. But we know that distinct sexes do exist among these minute creatures—that they propagate their kinds after the accustomed mode—and we hence fairly infer that fortuitous generation does not take place among them. May we not therefore conclude that the origin of those, first observed is similar to that of the thousands which we afterwards see produced according to the usual process? Nature does nothing in vain, and it is not consonant with her usual practice to suppose that she would authorize two distinct modes of creation in the same animal, where one. of these is evidently perfect and self-sufficing. It may therefore be laid down as a general rule, that all living beings proceed from others of a similar nature, either by generation, offset, or some other mθans; and that, in all instances of apparently spontaneous production, there has existed some minute or imperceptible germs, which deceive us by their sudden development! when placed under favourable circumstances. “In fact,"^ says Cuvier, “however feeble and minute the parts of an embryo or the seed of a plant may be at the moment we are first capable of perceiving them, they then enjoy a real life, and possess the germ of all the phenomena which that life may afterwards develope. These observations, extended to all the classes of living bodies, lead to this general fact, that there are none of those bodies which have not heretofore formed part of a body similar to itself, from which it has been detached.” “It is from them (their parents) they have received the vital impulse; and hence it is evident that, in the actual state of things, life proceeds only from life, and that there exists no other, except that which has been transmitted from one living body to another by an uninterrupted succession.” “Origin by generation, growth by nutrition, termination by death, are the general and common characteristics of all organized beings.^[10. Lectures on Çomp. Anat. , vol. í. ]”

At the same time it must be admitted, that the origin of many infusory and intestinal animals is sufficiently obscure. Of the latter class, one of the most extraordinary is a monstrous worm, as it may be called, which at distant intervals, and in parts of the world far removed from each other, has been found to inhabit the liver of the human race. The means by which it is bred, or the circumstances favourable to its production, are quite unknown; and some of the most philosophical inquirers of the present day have been unable to account for its origin, otherwise than by supposing that the viscus called the liver becomes, under certain circumstances, endowed with the power of actually secreting a substance capable of assuming and presenting the phenomena of distinct animal existence, and which, prior to the period of its being observed, had in fact become a specific animal ;—at least its existence, unlike that of mites, flies, &c. which so often misled die ancient naturalists (though “in limo non ex limo” is Ovid’s more accurate expression), cannot be accounted for in any other way. “There are,” Mr W. S. Macleay-observes,in his excellent and ingenious Horae Entomologicae, “ many circumstances which might be adduced to support the belief that, whether from disease or other causes, there are periods when other parts of a body besides the ovarium may produce living germs, and demonstrate thus the polype nature of the cellular substance.”

A polypus has been sometimes described as an animalized tube, capable of digestion, and possessed of a certain power of motion and reproduction; and these few words may be said to contain almost all that we know of its essential nature and attributes. As we advance in the scale of creation, we find a more complicated system of organs, with more varied powers of action, and a higher development of those accommodating instincts which, though circumscribed within certain impassable boundaries, yet seem at times to form such an approach to reason, as to connect the unvarying mechanical actions of the most simple zoophytical tribes with the conscious self-regulating power which has its final and most perfect development in the human race. The excellence of man, however, physically considered, consists more in the balance of various powers than in any one bodily superiority; for there is ’in,fact no single sense in which he is not excelled by one or other of the brute creation. Materialists, who regard the intellectual superiority of man as the result of his physical structure, must also, for the sakeof consistency,, maintain his excellence as a machine to be infinitely before[7:3:163] that of every other'animal. But as his indubitable superiority depends on something totally immaterial, which “throws him out of the group of animals, and makes him an insulated being,” there is the less necessity for either naturalists or metaphysical inquirers endeavouring to demonstrate the superexcellence of his physical condition. Man is in all cases “wonderfully,” and in many cases “fearfully made;” but in the powers of sight, touch, hearing, and smell, he is greatly surpassed by many animals; and even in the sense of taste, in which his practice is more varied and extensive, he is at least equalled by the great majority. It is indeed somewhat remarkable that the last-named sense, the only one in regard to which the human race can lay claim to the possession of equal excellence with the brutes that perish, should be the grossest and least intellectual of the whole.

Although it is by no means strictly true that the brain, cononsidered in relation to the size of the body, decreases as we descend from man to the lower tribes, because in many small birds, such as sparrows and finches, the brain is relatively much larger than in the human race, yet, exclusive of some such exceptions, it may be asserted that that important organ becomes less as we descend from mammiferous animals and birds, to reptiles, fishes, and other lower forms. Yet no very accurate conclusion can be deduced regarding the degrees of intelligence in different animals, from the proportion which the quantity of brain bears to the mass of the whole body, particularly when we come to compare animals of the same class with each other. It is in fact by no means easy to ascertain with accuracy what that proportion really is, because the weight of the brain is supposed to remain the same, while that of the animal varies according to its temporary condition, in this way only can we account for the contradictions which appear in the tabular views which have been given of these proportions by physiologists. Upon the whole, the smaller animals pertaining to the higher classes appear to have proportionally the largest brain, though man is in this respect seldom surpassed. The proportional weight of the brain to the body of man varies from l-22d to l-35th part, that of the gibbon or long-armed ape is is 1 to 40, that of the young malbrouk (Simia Faunus) as 1 to 24, that of the fox as 1 to 205, that of the beaver as 1 to 290, that of the field-mouse as 1 to 31, that of the elephant as 1 to 500, that of the horse as 1 to 400, that of the eagle as 1 to 160, that of the sparrow as 1 to 25, that of the canary-bird as 1 to 14, that of the cock as 1 to 25, that of the goose as 1 to 360, that of the land-tortoise as 1 to 2240, and that of the sea-tortoise as 1 to 5688.

Soemmering, Ebell, Vicq-d’Azir, Gall, and Tiedemann, supposed that every thing depended on the volume of the brain. But as Buffon and Daubenton had proved that the Sapajous have the brain proportionally larger than man, without surpassing their congeners in intelligence, it has been maintained by others that the volume alone was not a condition of superiority. Now the Sapajous in question have no convolutions to the brain, so that the surface of hat organ is represented by that of the interior of the cranium, and exceeds it in other cases in proportion as its folds are numerous and profound; and as there appears to be a constant relation among mammiferqus animals between the diminution of the cerebral surfaces and their ineffectual degradation, whilst no such relation can be traced between the degrees of degradation and the variations of the brain in respect to size, it has hence been inferred by some that the extent of surface, and not the volume of the brain, ought to be regarded as co-relative with the intellectual faculties.^[11. See Desmoulins, Rech. Anat. ct Phus., and the Journ. Compt. du Did. des Sciences Med. Septembre 1822. ]

In proportion, however, as the superior portion called the brain decreases in size, tide medullary matter appears to collect in other parts of the body, or in the eords which emanate from the brain; so that 'many animals with much smaller brains have nerves more voluminous in proportion to their bodies than those of man. This medullary substance, the medium of sensation >t is, in the human race especially, collected into one principal mass as the engine of thought and reflection, the intellectual attributes by which man is characterized; but it becomes dispersed in the inferior animals, or ramified over the whole body in the form of ganglions or nervous chords, without any preponderating superior brain. It is owing to this dispersion of the nervous system into these small separate centres in the polypus and other tribes, that almost every portion of the body, when separated from the rest, is capable of becoming a distinct animal, and of assuming an independent existence. In the lowest tribes of all, in which the nervous system has not yet been demonstrated, it probably consists of molecules of inconceivable minuteness, disseminated through the pulpy or gelatinous masses of which the bodies of many radiated and infusory animals are composed.

Singular effects result from the dispersion of the brain into so many small and separate centres; and this class of phenomena also illustrates the analogy which exists between the lower animals and the vegetable world. Among the superior creatures no reproduction takes place except of the fluids, and of whatever partakes of the nature of the epidermis. Injury is repaired and superficial parts renewed, but nothing resembling regeneration of important organs ever takes place. But it is otherwise with the inferior orders. The tentacula of the polypus and of many molluscous animals, the rays of the star-fish, the external members of the salamander, and the entire head, with the eyes and antennae of the snail, when cut off, are speedily renewed. There are also animals, such as the planaria, which reproduce by offsets after the manner of plants; and a polypus may be divided into many portions, each of which becomes perfect according to its kind ;—thus in a manner realizing what the ancient poets have feigned regarding the hydra of the Lernean marshes.

If the head of a mammiferous quadruped, or of a bird, is cut off, the consequences are of course fatal. But the most dreadful wounds that imagination can figure or cruelty inflict have scarcely any destructive influence on the vital functions of many of the inferior creatures. Riboud stuck different beetles through with pins, and cut and lacerated others in the severest manner, without greatly accelerating death. Lecuwenhoeck had a mite which lived eleven weeks transfixed on a point for microscopical investigation. Vaillant caught a locust at the Cape of Good Hope, and after excavating the intestines, he filled the abdomen with’ cotton, and stuck a stout pin through the thorax, yet the feet and antennae were in full play after the lapse of five months. In thebeginning of November, Redi opened the scull of a land-tortoise, and removed the entire brain. A fleshy integument was observed to form over the opening, and the animal lived for six months. Spallanzani cut the heart out of three newts, which immediately took to flight, leapt, swam, and executed their usual functions for 48 hours. Μ. Virey informs us, “Nous avons vu one salamandre vivant depuis deux mois, quoique décapitée au moyen d’une ligature serrée du cou.” A decapitated beetle will advance over a table, and recognise [7:3:164]a precipice on apþroachinġ the edge. Redi cut off the head of a tortoise, which survived 18 days. Colonel Pringle decapitated several libellulae or dragonflies, one of which afterwards lived for four months, and another for six; and, which seems rather odd, he could never keep alive those with their heads on above a few days.^[12. See the observations prefixed to the translation of Spallanzani’s Tracts, by John Graham Dalyell, Esq. ] 1

Some eurious particulars connected with the great tenacity of life in the lower animals are mentioned by Mr Fothergill. ^[13. Essay on Natural History. ]2 A friend being employed one day in the pursuit of insects, caught a large yellow dragonfly (Libellulo, varia), and had actually fastened it down in his insect box, by thrusting a pin through the thorax, before he perceived that the voracious creature held a small fly, which still Struggled for liberty, in its jaws. The dragonfly continued devouring its victim with great deliberation, and without expressing either pain or constraint, and seemed totally unconscious of being pinned down to the eork, till its prey was devoured, after which it made several desperate efforts to regain its liberty. A common flesh-fly was then presented to it, when it immediately became quiet, and ate the fly with greediness: when its repast was over it renewed its efforts to escape. This faet being mentioned to Mr Haworth, the well-known English entomologist, he confirmed the truth of the remarkable insensibility to pain manifested by insects, by narrating an additional circumstance. Being in a garden with a friend who firmly believed in the delicate susceptibility of these creatures, he struek down a large dragonfly, and in so doing unfortunately severed its long abdomen from the rest of the body. He caught a small fly, which he presented to the mutilated insect, by which it was instantly seized and devoured; and a second was treated in the same manner. Mr Haworth then contrived to form a false abdomen, by means of a slender portion of a geranium; and after this operation was performed the dragonfly devoured another small insect as greedily as before. When set at liberty, it flew away with as much apparent glee as if it had received no injury. It is a fact well known to practical entomologists, that large moths found asleep during the daytime may be pinned to the trunks of trees without their appearing to suffer such a degree of pain as even to awake them. It is only on the approach of the evening twilight that they seek to free themselves from what they must no doubt regard as an inconvenient situation.

The cruelty of zoological, especially of entomological pursuits, has too often been stated as an objection to the practical parts of the study of natural history. When a noble aristocrat (who thinks it sport to shoot a shepherd’s dog) slaughters 100 brace of grouse in a single day, we hear nothing of such an objection, possibly because the flavour of moor-game is very exquisite; and the reason of defence is good. But the tastes of men differ, and fortunately, as all have not the means of an equal gratification from the same source. “Cruelty,” say Messrs Kirby and Spence, “is an unnecessary infliction of suffering, when a person is fond of torturing or destroying God’s creatures from mere wantonness, with no useful end in view; or when, if their death be useful and lawful, he has recourse to circuitous modes of killing them, where direct ones would answer equally well. This is cruelty, and this with you we abominate; but not the infliction of death when a just occasion calls for it. They who see no cruelty in the sports of the field, as they are called, can never, of course, consistently allege such a charge against the entomologist; the tortures of wounded birds, of fish that swallow the hook and break the line, or of the hunted hare, being beyond comparison greater than those of insects destroyed in the usual mode. With respect to u⅛ lity, the sportsman, who, though he adds indeed to ⅛ e ] general stock of food, makes amusement his primary 0 b- k jeet, must surely yield the palm to the entomologist, who adds to the general stock of mental food, often supplies hints for useful improvement in the arts and Sciences and the objects of whose pursuit, unlike that of the for-’ mer, are preserved, and may be applied to use for many years. But in the view of those even who think inhumanity chargeable upon the sportsman, it will be easy t 0 place considerations which may secure the entomologist from such reproof. It is well known, that in proportion as we descend in the scale of being, the sensibility of the objects that constitute it diminishes. The tortoise walks about after losing its head; and the polypus, so far from being injured by the application of the knife, thereby acquires an extension of existence. Insensibility almost equally great may be found in the insect world. This, indeed, might be inferred a priori, since providence seems to have been more prodigal of insect life than of that of any other order of creatures, animalcula perhaps alone excepted. No part of the creation is exposed to the attack of so many enemies, or subject to so many disasters; so that the few individuals of each kind which enrich the valued museum of the entomologist, many of which are dearer to him than gold or gems, are snatched from the ravenous maw of some bird or fish, or rapacious insect, would have been driven by the winds into the waters and drowned, or trodden under foot by man or beasts; for it is not easy in some parts of the year to set foot to the ground without crushing these minute animals; and thus also, instead of being buried in oblivion, they have a kind of immortality conferred upon them. Can it be believed that the beneficent Creator, whose tender mercies are over all his works, would expose these helpless beings to such innumerable enemies and injuries, .were they endued with the same sense of pain and irritability of nerve with the higher orders of animals ?” ^[14. Introduction to Entomology, vol. L p. SC. ]3 Instead, therefore, of believing, and being grieved by the belief, that the insect we tread upon,

In corporal sufferance finds a pang as great As when a giant dies, the very converse is nearer the truth. “Had a giant lost an arm or a leg,” continue the authors just quoted, “or were a sword or spear run through his body, he would feel no great inclination for running about, dancing, or eating. Yet a tipula will leave half its legs in the hands of an unlucky boy who has endeavoured to catch it, and will fly here and there with as much agility and unconcern as if nothing had happened to it; and an insect impaled upon a pin will often devour its prey with as much avidity as when at liberty. Were a giant eviscerated, his body divided in the middle, or his head cut off, it would be all over with him; he would move no more; he would be dead to the calls of hunger, or the emotions of fear, anger, or love. Not so our insects: I have seen the common eockehafer walk about with apparent indifference after some bird had nearly emptied its body of its viscera; a humble bee will eat honey with greediness though deprived of its abdomen; and I myself lately saw an ant, which had been brought out of the nest by its comrades, walk when deprived of its head. The head of a wasp will attempt to bite after it is separated from the rest of the body; and the abdomen, under similar circumstances, if the finger be moved to it, will attempt to sting.” Query, which part felt conscious of being the original wasp?

That the acuteness of bodily suffering, even among the
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, ioher classes of the brute creation, is in some manner ∣4rovidentially subdued, and rendered so much less acute √s not to be a fit subject of comparison with the suffering if the human race, is indeed evident from various pheno-nena, whatever the cause may be. The writer of this .rticle has seen a turtle-dove (Columba risoria) which zas so severely lacerated by a cat, that the contents of ts stomach were torn out. The painfully excited sympathy of those who had long cherished the gentle crea-ure was, however, in a great measure allayed by see- ∏g the bird immediately afterwards proceed to pick up he fresh grains of barley which (till the aid of the surdon was called in) continued to fall from its wounded launch.

Considerations of the nature glanced at in the preced-ag paragraphs can never, of course, be so misconstrued s to afford any palliation to wanton or inconsiderate ruelty to the brute creation. The judges of the Areo- ∣agus who condemned to death the child whose amuse-αent it had been to pluck out the eyes of quails, were egulated in their determination by the motives imput-d to the young criminal, and which they deemed expressive of so cruel and pernicious a character, that in ∣fter-times he would assuredly offend the state. “Nec nihi videntur Areopagitae,” says Quintilian, “cum dam- ∣averunt puerum coturnicum oculos cruentem, aliud ju-licasse, quam id signum esse perniciosissimae mentis, Rultisque malo futurae, si adolevisset.”^[15. De Inst. Orat. lib. v. cap. ix. de Signis. ] But had some ,∙reat oculist, intent on the structure and physiology of he human eye, and engaged in a difficult course of ∙ex-ιerimental observation, by means of which the “dim affusion” which often veils the orbs of his fellow-men night be obviated or decreased, found himself under the necessity of having recourse to a somewhat similar operaion, the case would have assumed another character, and he most sentimental philanthropist must have applauded he practice of the philosopher. So it is in a great mea-ure with the pursuits of the naturalist. If the wonderful tructure of the lower orders of creation cannot be studied >r understood, or their infinitely varied forms held in re-nembrance, without hastening by a few days or hours the crmination of that brief career which in truth scarcely !ver meets with a strictly natural end, then is the student >f nature, following out the principles of an elevating and ntellectual pursuit, as well entitled to command a portion of animal life as he who, to pamper the refined gross-jess of a sensual appetite, bleeds his turkeys to death )y cutting the roots of their tongues, boils crabs and obsters alive, and swallows unsuspecting oysters by the Score.

The more perfect the nervous system, the greater is the legree of intelligence. Indeed, were it not that no trace )f that system has yet been discovered in many zoophytes, ve might almost assert that the presence of nerves constitutes animal life, and that their absence in organized natter reduces it to the vegetable state. The greater the extent of brain in proportion to the size of the body, the greater in general the degree of sensibility. A French ìnatomist, in dissecting a horse of which he had admired the noble qualities, exclaimed, “J’ai long temps douté si nous avions le droit de monter sur ton dos; mais en voyant la petite capacité de ton cerveau, je n’en doute plus maintenant; tu n’est qu’une bête.” The most perfect animals ire such as are provided with a head which serves as the centre of their sentiments and sensations, and with a mouth for the reception of their nourishment. Their forms ire symmetrical, or composed of two equal parts; they change their place by a voluntary act; their sexes are distinct, and separately incapable of continuing the species; they are provided with five senses, and endowed with the perception of pleasure and of pain. The inferior tribes, on the contrary, which present so many analogies to the vegetable kingdom, have no distinct head, or single organ of life; they are not symmetrical or composed exactly of two equal parts, but rather affect the circular or radiated form; and for the most part they either remain fixed to the place which gave them birth, or with difficulty change their places of abode. The sexes are frequently united in the same individual, and their senses are limited to such as are necessary to a very confined and almost vegetative existence.

Though no animal has more than five senses, a great many are much more sparingly endowed. The only universal sense seems that of touch. The next to be developed is probably that of taste, then sight, hearing, and, lastly, smell. In the human race the senses are more equally balanced than in the brute creation, among the different tribes of which we find many animals as remarkable for their extreme acuteness in certain senses, as for their obtuseness in respect to others. The sense of smell in the dog, excepting some artificial varieties, such as the greyhound, prevails over every other; birds of prey are remarkable for their keenness of sight; the sense of hearing is strong in the hare; that of touch in the trunk of the elephant; that of taste in the lord of the creation. It follows as a consequence that the dog is by nature a hunting animal; that the eagle, upborne upon resplendent wing, describes its magnificent circles in the air, “sagacious of its quarry from afar ;” that the hare couches securely among the long dewy grass, with its head so low that its eyes must be almost useless, but trusting to its quicker ears, which warn it of an approaching foe; that the elephant examines the exact nature of all objects by touching them with the fleshy finger of its proboscis; and that Mrs Rundell’s work on cookery has run through nineteen editions. All insects in the perfect state, and the greater proportion of their larvae, a part only of the molluscous tribes (such as the inhabitants of univalve shells), crustaceous animals, such as crabs and lobsters, and all fishes, reptiles, birds, and quadrupeds, enjoy the sense of sight; and all these classes (with the exception of insects and many of the mollusea) are also furnished with the organs of hearing. That the latter sense, however, also exists in insects, may be fairly inferred from the frequent and varied sounds which they are capable of producing, although the seat of the faculty has not yet been ascertained. Many zoophytical tribes, which have no special organs of sight, appear to become sensible to the presence and action of light, through a delicate perception of the sense of touch. According to Buffon, the sense which has the strongest affinity to thought is that of touch; and he regards it as being enjoyed by man in greater perfection than by animals. That which has the strongest affinity to instinct and appetite is smell,—a sense in which man must acknowledge an infinite inferiority. Hence, according to the Frenchman, man has the greatest tendency to knowledge, and the brute to appetite. There is no doubt that in man and the different species of monkeys the sense of touch is highly discriminating; but it is assuredly a false view of the subject which has led Helvetius and others to attach such an extraordinary degree of importance to the hand, as the medium of intellectual superiority in the human race.

Whatever exhibits the phenomena of either animal or [7:3:166]vegetable life, advances towards the perfect development of its parts through the medium of aliment. This name is applied to the numerous and diversified substances which, when introduced into the system of an organized body, have the power of identifying themselves in part with that system, in such a manner as to effect its nourishment, reparation, and increase. “Nourishment,” says Bacon, “ought to bee of an inferior nature and more simple substance than the thing nourished. Plants are nourished with the earth and water, living creatures with plants, man with living creatures. There are also certain creatures feeding upon flesh; and man himself takes plants into a part of his nourishment: but man and creatures feeding upon flesh are scarcely nourished with plants alone. Perhaps fruits or graines, baked or boyled, may with long use nourish them, but leaves of plants or herbs will not doe it; as the order of the Foliatanes showed by experience living creatures are nourished by the mouth; plants by the root; young ones in the womb by the navill; birds for a while are nourished with the yolke in the ε-gge, whereof some is found in their crops after they are hatched. All nourishment moveth from the centre to the circumference, or from the inward to the outward: yet it is to be noted, that in trees and plants the nourishment passeth rather by the barke and outward parts than by the pith and inward parts; for if the barke be pilled off, though but for a small bredth round, they live no more: and the blood in the veines of living creatures doth no lesse nourish the flesh beneath it than the flesh above it. Vegetables assimilate their nourishment simply without excerning; for gums and teares of trees are rather exuberances than excrements; and knots or knobs are nothing but diseases. But the substance of living creatures is more perceptible of the like; and therefore it is conjoyned with a kinde of disdaine, whereby it rejecteth the bad and assimilateth the good. It is a strange thing of the stalkes of fruits, that all the nourishment which produceth sometimes such great fruits should be forced to passe thorow so narrow necks, for the fruit is never joyn’d to the stock without some stalkes. It is to be noted, that the seeds of living creatures will not be fruitful but when they are new; but the seeds of plants will be fruitful a long time after they are gathered; yet the slips or cions of trees will not grow unlesse they be grafted green, neither will the roots keepe long fresh unlesse they be covered with earth.”^[16. History, Naturali and Experimental, of Life and Death. English translation, 1638. ]

Nutritive substances of course vary according to the nature of the bodies which consume or absorb them. Plants derive their chief nourishment from air and water, the former of which must contain carbonic acid gas, the latter the dissolved remains of animal or vegetable substances. It is, however, possible to produce vegetable growth from pure water, assisted by warmth and air. Vegetables, again, serve as food to the greater proportion of animals, and these in their turn are devoured by the carnivorous few. It is thus that the productions of nature are connected together in one great circle, and are reciprocally dependent on each other. Without water there could be neither plants nor herbivorous animals, and without herbivorous animals there could be no carnivorous ones; therefore, without water there could be no life. Inorganic matter furnishes the first and most simple materials of existence; organic bodies perislr and become decomposed, and thus adding to the mass of inorganic matter which they had for a short period abandoned, they enter again as elements into the composition of other and more complex forms. Indeed, according to Mr W. S. Macleay, organized matter is nothing but a pecu liar modification of brute matter acted upon by the vital principle; but this form of expression probably throws 1 no new light upon the subject. ∖

We may here present a remark not unworthy of attention regarding the nature of the flesh in the different classes of the animal kingdom. Considered as a viand, the flesh of animals becomes less substantially nourishing as we descend in the scale. For example, the flesh of a quadruped contains a greater quantity of nourishment in proportion to size and weight than that of a bird, while the latter exceeds in that respect both reptiles and fishes. Hence in catholic countries the latter are justly regarded as meagre, and form an exclusive food during the frequent days of abstinence by which it is sought to mortify ft e flesh. Shell-fish and Crustacea, and a fortiori the zoophytical tribes, yield a still smaller proportion of nutritious matter. A revolting conclusion has been drawn from this alleged relation between the flesh of a highly organized animal and the power and excellence of its nutritive qualities; viz. that cannibalism, or the habit of anthropophagous nations, opens up to those unnatural tribes a pleasure connected with the indulgence of the sense of taste greatly surpassing what is enjoyed by those who confine their mastication to the brute creation; because, in accordance with the rule supposed, the organic perfection and highly animalized nature of man is productive of a higher degree of nutrition, and of a greater capability of direct assimilation, when the substance of which he is composed is used as food by his fellow-mortals. But the scale of alimentary substances may rather be said to commence with air and water, and to terminate with the herbivorous animals; for the flesh of carnivorous kinds is, with very few exceptions, of a nature inadequate to the healthy sustenance of life. It is of a quality too putrescent, and decomposes with too great rapidity, as if the organization of matter could make no further progress, but passing rapidly from one extreme to another, hastened to throw off even the semblance of life, to assume again the simplest elementary form. “Over-great affinity,” says Bacon, “or consubstantiality of the nourishment to the thing nourished, proveth not well; for creatures feeding upon herbs touch no flesh; and of creatures feeding upon flesh few of them eat their owne kinde. As for men which are cannibals, they feed not ordinarily upon men’s flesh, but reserve it as a dainty either to serve their revenge upon their enemies, or to sa-tisfie their appetite at some times. So the ground is best sowne with seed growing elsewhere; and men do not use to graft or innoculate upon the same stocke.”

Mineral bodies are still more unfit for the purposes of nutrition. They furnish both medicines and poisons in abundance, but never aliments. The difference between these objects may be shortly stated as follows: Aliments are substances alterable by the action of the organs which appropriate them; medicines act on the organs, of which they alter or modify the action; poisons attack and extinguish life itself. But according to the specific nature of different animals, and various other circumstances, the qualities of these agents are convertible, so that aliments become poisonous, and poisons alimentary. Thus opium, which among European nations is a medicine, and too frequently a poison, has become, according to the practice of several eastern nations, an alimentary substance. Aloes, which are simply medicinal for the human race, are a destructive poison to many carnivorous animals. On the other hand, according to Pallas, hedgehogs eat abundantly of cantharides without being in the slightest degree incommoded by them; and bees are known to feed [7:3:167]upon and form their honey from the secretions of many perrnicious and even poisonous plants. The caterpillar of a certain sphinx moth is highly delighted with the acrid and venomous fluid of a tithymalis.

The more that animals enjoy the qualities of youth, strength, and activity, the greater is the increase and development of their parts, and the greater the necessity for an abundant supply of food. Of many individuals exposed to an absolute abstinence of many days, the young are always the first to perish. Of this the history of war and shipwreck offers in all ages too many frightful examples, There are several instances on record of an almost total abstinence from food for an extraordinary length of time. Captain Bligh, of the Bounty, sailed nearly 4000 miles in an open boat, with occasionally a single small bird not many ounces in weight for the daily sustenance of 17 people; and it is even alleged, that 14 men and women of the Juno, having suffered shipwreck on the coast of Arracan, lived 23 days without any food. Two people first died of want on the fifth day. In the opinion of Rhedi, animals support want much longer than is generally believed. A civet cat lived 10 days without food, an antelope 20, and a very large wild cat also 20; an eagle survived 28 days, a badger one month, and several dogs 36 days. In the memoirs of the Academy of Sciences there an account of a bitch, which having been accidentally shut up alone in a country-house, existed for 40 days without any other nourishment than the stuff on the wool of a mattress which she had torn to pieces. A crocodile will live two months without food, a scorpion three, a bear six, a chameleon eight, and a viper ten. Vaillant had a spider that lived nearly a year without food, and was so far from being weakened by abstinence, that it immediately killed another large spider, equally vigorous but not so hungry, which was put in along with it. John Hunter inclosed a toad between two stone flower-pots, and found it as lively as ever after 14 months. Land-tortoises have lived without food for 18 months; and Baker is known to have kept a beetle in a state of total abstinence for three years. It afterwards made its escape.^[17. See the observations prefixed to the translation of Spallanzani’s Tracts, before referred to. ] Dr Shaw gives an account of two serpents which lived in a bottle without any food for five years.

The necessity of aliment becomes less vividly felt during sleep, and certain other periods of prolonged repose. There are several animals which hybernate, or go into winter quarters for six months in the year, during which period many of them require no food, but are maintained solely by that excellence of bodily condition which they had acquired during a prior period of activity and good cheer. This leads us naturally to consider what is called the hybernation of animals.

Many creatures are so constituted that the activity of their functions is greatly impaired by a comparatively slight reduction of temperature. Naturalists and anatomsts have alike sought in vain for either external or internal characters of general application, by which they light distinguish, a priori, the species subjected to this strange though well-ordered lethargy. They belong to various genera and tribes, many of which have few chacters in common, as will be perceived when we name well-known instances the dormouse, the hedgehog, and the bat. It influences both warm and cold-blooded animals. The former of these, at certain advanced periods the autumn, according to the species, seek out places of repose, either in the earth, among old walls, in caverns, trunks of trees, or bushes; which retreats they usually line with dried herbs, grasses, leaves, or moss. The bat chooses caverns, churches, barns, and other situations where the temperature is milder than that of the open air; and, contrary to the usual practice, it suspends itself by the hooked claws of its hinder extremities. It is the practice of other hybernating animals to contract themselves into a ball, in such a manner as to expose the smallest possible surface to the action of the air. When discovered in their retreats they are generally thus rolled up, cold to the touch, their limbs stiffened, their eyes closed, their respiration slow, interrupted, sometimes even imperceptible, and their insensibility so great that they may be removed, rolled about, and otherwise maltreated, without showing any further signs of life.

It has been observed that the temperature of these animals gradually lowers itself as the season declines. Their respiration also becomes slower, their motions less lively, and their appetite diminishes: but sensation and the power of locomotion still continue. This intermediate state between the perfect performance of the vital functions and confirmed torpidity endures for several weeks; the degree of temperature at which different animals become entirely overpowered varying, of course, according to the species. The propensity has been observed, in the following well-known animals, to correspond to a scale of descending temperature, according to the following order:—1st, The bat; 2dly, the hedgehog; 3dly, the dormouse; ⅛tldy, the marmot; ĩ>tidy, the hamster. Although many other animals are subject to the same law, it is only among those just enumerated that an exact comparison has been instituted.

A complete state of hybernation consists in the suspension of sensation and voluntary motion, in addition to a great decrease in the temperature of the body, and in the frequency of respiration. Its different degrees of intensity are well ascertained by the number of respirations in a given time, or, in its most perfect state, by the total suspension of all respiratory movements. The different species of the bat tribe are those of which the torpidity is the least profound; and the marmot probably experiences the greatest degree of vital suspension. The temperature of these animals during their lethargy depends in a great measure upon that of the external air, and is consequently variable. It is in general, however, superior to it by several degrees. It may descend to within a few degrees of the freezing point, but is not susceptible of reduction to that point, without producing either re-action of the vital functions Or death. There is, therefore, contrary to the opinion of some of the older naturalists, a degree of external cold incompatible with the torpidity or existence of these animals. The species most easily rendered torpid, such as the bat, the hedgehog, the dormouse, the lerot, and the muscardine, cannot support a cold of 14° of Fahrenheit. A warmth of from 50° to 53° brings them v again to life. Sundry mechanical means, such as different degrees of motion, serve to restore several of the last-named species without any increase of temperature; but to preserve them in a state of prolonged activity, a gentle warmth must be applied and continued.

It is evident, from these and other observations, that the sleep of mammiferous animals is not characterized by, a uniform and constant duration. As it is dependent on the variations of the atmosphere, it will commence at an earlier, continue a longer, or be interrupted after a shorter period, according to the difference in the seasons of particular years, the skill which the animals may have exhibited in the choice of a protecting habitation, or the peculiar constitution of the species, or even of the individuals. The habit of storing up a supply of winter provisions also depends upon their greater or less degree of exposure to [7:3:168]the power of awakening influences. The hedgehog, for example, has been observed to form several separate magazines, to which it has recourse during the winter season; and the marks of its little feet have sometimes been traced on the surface of the surrounding snow. .

The hybernation of the swallow is a point on which very dissimilar opinions have been promulgated. It now appears to be the prevailing belief that these birds migrate on the approach of winter to other and more genial climes, but that cases do occur in which such individuals as are prevented by circumstances from joining the “marshalled array,” are enabled to survive the rigours of our northern winters by the power which their constitution possesses of assuming the torpid state; at least the occurrence of torpid swallows, however rare, is too well authenticated to be a matter of doubt.

It is said that the tanrec, a species of hedgehog found in Madagascar, becomes torpid for some months in the year. If this assertion is well founded, it affords the only known instance of torpidity in a mammiferous quadruped of a warm climate.

Many cold-blooded animals may be regarded as of the hybernating kind. Indeed the greater proportion of reptiles, insects, molluscous animals, &c. inhabiting cold countries, are very lethargic during the winter season, which they usually pass without food. They appear subject to the influence of this feeling even in warm climates; at least Humboldt describes certain reptiles in South America which pass a portion of the year buried in the earth, and which are only aroused by the occurrence of rainy weather or the excitement of violent means. “The manners of animals,” says this enlightened observer, “vary in the same species, according to local circumstances difficult to investigate. We were shown a hut, or rather a kind of shed, in which our host of Calabozo, Don Miguel Cousin, had witnessed a very extraordinary scene. Sleeping with one of his friends on a bench covered with leather, Don Miguel was awakened early in the morning by violent shakes and a horrible noise. Clods of earth were thrown into the middle of the hut. Presently a young crocodile, two or three feet long, issued from under the bed, darted at a dog that lay on the threshold of the door, and, missing him in the impetuosity of his spring, ran toward the beach to attain the river. On examining the spot where the barbacon or bedstead was placed, the cause of this strange adventure'was easily discovered. The ground was disturbed to a considerable depth. It was dried mud, that had covered the crocodile in that state of lethargy, or summer sleep, in which many of the species lie, during the absence of the rains, amid the llanos. The noise of men and horses, perhaps the smell of the dog, had awakened the crocodile. The hut being placed at the edge of the pool, and inundated during part of the year, the crocodile had no doubt entered, at the time of the inundation of the savannahs, by the same opening by which Mr Pozo saw it go out. The Indians often find enormous boas, which they call υji, or waterserpents, in the same lethargic state. To re-animate them, they must be irritated, or wetted with water.”^[18. Personal Narrative, vol. iv. p. 380. ]

Upon the whole, naturalists seem to be of opinion that no species of animal is condemned to torpidity by any inherent property of its nature. It is a provisional faculty, dependent on external circumstances, and may be interrupted, postponed, or altogether prevented, by regulating the conditions under which the animal is placed.

The disposition of animals in relation to other individuals of the same species differs considerably. There are some which unite in couples and divide between them the cares of the family. This is usually the case among the various tribes of birds, and also among carnivorous quadrupeds; whilst the males of such as feed on veg¢.' tables, and which consequently find almost everywhere an abundant and easy nourishment, abandon to the mother the rearing and education of their young. It has also been observed, that among such birds as feed on liv. ing prey, the male is very assiduous in assisting his male to procure a sufficient supply. But naturalists have erred in assigning the polygamous habit as a general charac∙ teristic of the gallinaceous kinds. The instinct to pair, or the habit of monogamy, is no doubt only bestowed on those species to which it is necessary for the rearing of their offspring, and differs considerably in the nature and permanence of the attachment, according to the position of the nest, i. e. whether it is built upon or above the surface of the ground. All birds which build on trees, as was long ago remarked by Lord Kames, are hatched blind, and almost without feathers, and consequently require the sedulous care of both parents. But the generality even of gallinaceous birds, which breed upon the ground, do likewise pair, though the hatching of the eggs is entirely confined to the female, who completes her task by leading the young to their proper food, which they are able immediately to pick up for themselves, being active and well feathered from their birth. The male, at the same time, continues to manifest a certain degree of paternal solicitude, by uttering the alarm-note on the approach of birds of prey, or other dangerous foes. Black game and woodgrouse, however, do not appear to pair at all; but in the spring a male bird assembles a certain number of females about him, which afterwards deposit their eggs, and rear their young altogether independent of the male parent. They are therefore polygamous in the proper acceptatiqn of the term. Even among herbivorous quadrupeds pairing is rare, because the female can suckle her young while she herself is feeding; but the monogamous habit probably obtains among most carnivorous quadrupeds, and certainly among all carnivorous birds, because incubation leaves the female no sufficient time to hunt for food,^[19. See Kames’s Sketches ] and because young birds cannot bear a long fast, and therefore require the assistance of both parents, while unable to provide for themselves. The association or fellowship of birds is either annual or for life; the former bond is the more usual, though eagles, crows, and several other species afford examples of a long-continued attachment.

Many birds assemble in autumn, winter, and early spring, into flocks, but as soon as the pairing season has commenced they again separate into pairs. Others again appear to be more gregarious during the breeding season than at any other period of the year, for example the gannet or soland-goose (P. bassanus) ; but this arises not so much from a love of fellowship with their kind, as from the accident of there being few places fitted for the purposes of nidification and the rearing of the young.

We have said that pairing is rare among such quadrupeds as feed on grass, because the female can feed herself at the same time that she is suckling her young. The roe-deer, however, among herbivorous quadrupeds, forms an exception to the general rule. On the other hand, there are several carnivorous quadrupeds which do not pair, but the young of which are left entirely dependent on the mother; that is to say, the latter is obliged both to capture her own food and to suckle her offspring-

Among gregarious quadrupeds which usually store up food for winter, pairing is probably necessary to prevent discord, and in this respect beavers are said to resemble those birds which place their nests upon the ground. As [7:3:169]soon as the young are produced, the males abandon their stock of food to their mates, and live at large, but return •frequently to visit them while they are suckling their young. Hedgehogs and most of the monkey kind pair. Seals are polygamous, and turtles leave their young to be hatched by the heated sand. Earwigs, spiders, bees, and woodlice (onisci), are amongst the few of the insect tribes which pay any attention either to their eggs or offspring. The young of the greater proportion of animals is produced in spring, when the supply of food is the most abundant, ιnd when the long period which intervenes before the approach of winter enables them to acquire strength to support the rigours of that inclement season.

Though the period of gestation varies considerably in the Efferent quadrupeds which feed on grass, yet the females ire regularly delivered in spring, or early in summer, when the herbage is nutritive and abundant. The mare conceives in summer, carries 11 months, and brings forth in May. The same is nearly the case with the cow. The sheep and the goat are usually in season in November; they carry five months, and produce when grass has begun to spring. They love short, close herbage, upon which a [horse or cow would barely thrive. The ass is in season liboutthebeginningofsummer,butshe bears twelvemonths, ιnd consequently brings forth likewise early in summer. Wolves and foxes copulate in December, but as they only bear five months, they bring forth in April, when the season has assumed a genial aspect, and animal food is as abundant as at any other season. If we were to guess what would probably be the rutting season of animals, we would say summer, especially in a northern country; and yet, to quadrupeds which carry their young only for four or five months, such economy would be injurious and improvident, as it would bring the time of delivery at an undue season, both for warmth and food.^[20. Kames’s Sketches. ] There are a few exceptions to the above rule, which, however, in themselves, belong to an equally beautiful system of providential ordinances. Some gregarious and store-collecting animals, for example, bring forth in January, when their granary of provisions is still abundantly filled.

The season of pairing, or of production, among wild animals, usually takes place only once a year, and at a fixed period; but those which man has rendered domestic are observed to couple at all seasons. The species of warmer climates, when transported into colder regions, usually cease to pair, or at least their union is unproductive; and the same consequence generally follows a state of captivity. Among such species, however, as man has fairly reduced to a state of satisfied domestication, the individuals become much more prolific than in the wild state.

The season of love varies greatly among mammiferous animals. The greater proportion pair in spring and summer; but the wolf pairs in winter, the stag in autumn, and many domesticated animals at diversified periods throughout the year. Prolific union takes place among varieties of the same species; and it is by paying attention to these that the finer races of our domestic animals are maintained and continued. As the climate of northern countries causes several of our most valuable animals to degenerate (as it is called), it has been customary to obtain from time to time a male animal of a pure and noble race, which, when paired withan ordinary female, produces a breed scarcely inferior to the male parent; for it has been observed that, with few exceptions, the new produce assumes the characteristics of the father. Thus, in uniting * s 11 θ c P °f an ordinary kind with a ram of the Merino race, th Wi lst S eneratl0n almost equals the father in beauty.

Vhat is frequently called deterioration in animals is, more properly speaking, their natural assumption of those peculiar -attributes which fit them for the inclemencies of climates uncongenial to their original nature. A Laplander is no more a deteriorated Asiatic of the Mongolian or Caucasian line, than a Georgian or Circassian is a highly refined Laplander; neither is the Shetland pony a deteriorated Arabian courser, any more than the steed of Araby is a thorough-bred shelty. Each has been enabled by a wise provision of nature to assimilate its character and constitution to the qualities of the climate in which it was destined to exist; and had it been incompetent to effect or undergo such assimilation, it would then indeed have deteriorated—that is to say, it would have died. If we admire the slim smooth elegance of the Italian greyhound, and regard the rough shaggy coat of the dog of Nova-Zembla as a deterioration, let us remember that that which is the beauty of the one would be the bane of the other; and what would then become of that forlorn agriculturist, whose business it is to drill the ice and to furrow the snow? The small stature and peculiar habits of the northern pony would have been as little fitted to sustain the fiery breath or the shifting sands of an eastern desert, as the graceful Arabian to withstand the cold and cloudy clime, and the rugged and precipitous mountains, of Lapland or Thule. Therefore, instead of being deteriorated, each ought rather to be said to exist in the best and most improved condition, according to the nature of its particular calling. Using the word, however, in its more usual acceptation, it may be stated that an animal seldom degenerates in its native country, but more frequently in those for the climate of which its constitution is not adapted. Each species appears to have a certain extent or circle of natural distribution, in the centre of which it not only most abounds, but also there shows itself in its finest and most characteristic proportions. As the places of its occurrence diverge from this centre of dominion, it becomes rarer, and exhibits a variation or considerable departure, at least in its external characters, from the primitive model. Thus the horses of Arabia and Barbary degenerate in Britain; and, to preserve the breed in purity, they must be frequently crossed by the original; but the Arabs themselves are very careful to prevent any mixture in the blood of their native and noble kinds, and would deem them deteriorated by such alliance.

In the tabular or abridged views of classification which we here present, it is our intention merely to exhibit the great primary divisions of the animal kingdom called classes. The secondary divisions into orders, and the further dismemberment of these into minor groups called families, genera, &c., will be illustrated when we come to treat of each class in particular under its proper head. Neither do we intend to trace the progress of classification from the’earliest ages of scientific record; because, as the object of the naturalist is rather to ascertain the nature and relationship of things as they are, than as they were supposed to be, there is the less necessity for leaving our direct route, to trace either the origin or the progress of error. We shall proceed, after a few observations, at once to the system of Linnaeus, which is in fact the basis of all that have succeeded, and without a knowledge of which it is impossible to understand either the merits or defects of more recent systems. Indeed, with the exception of the purely artificial classification of Klein, and the multiplied orders of Brisson and Vicq-d’Azir, all the systems which have appeared since the middle of last century are indebted more or less to the labours - of the immortal Swede, and may be valued almost exactly in pro [7:3:170]portion to their share in the lucidus ordo of the Linnaean system. For example, the Systema Regni Animalis of Erxleben (1777) is nothing more than a revised edition of the Systema Naturae, in which are engrafted, with no lack of skill, many additions both of species andgenera; the whole being presented in a consecutive series, without the accustomed subdivision into the primary groups called orders. The Prodromus Methodi Animalium of Storr (1780) does not differ radically from the Linnaean system. The Eļcnehus Animalium of Bodaert (1787) is allied to it still more closely in every thing except its accuracy. Of Gmelin’s work (1789) we need not speak, as it is a professed révisai (being the 13th) of the Systema Naturoe. And although no one will deny the merit of profound and original inquiry to the investigations of Blumenbach, most readily will those who are best acquainted with his labours admit, that in zoology he has wisely followed the footsteps of Linnaeus. The six classes into which the German naturalist divides the animated creation, viz. Mammalia, Aves, Amphibia, Pisces, Insecta, and Vermes, correspond with those of the Linnaean arrangement, although their orders and genera are in some respects differently combined. His motto appears to have been Multa fiunt eadem, sed aliter. (Quintilian.)

The signal benefits conferred on natural history, in all its branches, by the learning and genius of Baron Cuvier, are known wherever the science has obtained a zealous and successful cultivator; and it cannot have escaped the notice of the critical observer, that after 30 years of profound and philosophical research into the mysteries of the animal kingdom, the most enlightened zoologist of the age should have finally reverted to a closer approximation to the Linnaean system, than had characterized his views at any former period of his brilliant career. When he first made known (in 1797), conjointly with M. Geoffroy, his new classification of mammiferous animals, his numerous genera were contained under no less than 14 different orders. Thirty years afterwards (in 1817) he published his Règne Animal, with many improvements in the composition and arrangement of the minor divisions, and with the addition of the order of which he is himself so bright an ornament, but otherwise composed (we speak at present of the mammalia alone) of primary divisions exactly the same in number, and nearly the same in nature, as those finally divulged and established by Linnaeus himself just GO years before.

Latreille, Dumeril, Desmarest, and Frederick Cuvier, are followers or coadjutors of the Baron, and with him are partakers in the modification and amendment of the Linnaean system. The venerable Lamarck has greatly signalized himself in a field which, it must be confessed, was obscure to the eye of Linnaeus—that of the molluscous animals—-which, under the name of Vermes Testacea, were but indifferently treated in the Systema Naturoe. The error appears to have lain in the greater attention which was bestowed on the shells themselves, or testaceous coverings, than on the animal inhabitants; and the consequence has been, that the conchologist of the old school ranks with the collector of china, whether old or new.

The names above enumerated are certainly among the foremost in the annals of modern science; and although, in addition to these, many more might be mentioned with honour as having contributed, by monographs or other partial though highly prized contributions, to the increase of knowledge, yet we are not aware that more than three systematists of acknowledged and wide-spread influence, or of what may be termed universal celebrity, remain unnoticed, of those who have essentially influenced the present condition of zoological ' science; we mean Fabricius, Illiger, and Μ. de Blainville. Wc have no hesitation in asserting, that as the writers first mentioned owe much of the success which has attended their labours to their having judiciously engrafted their own improvements on the original stock of the Linnaean system, so the au∙ thors last named, though not less highly gifted, have ⅛a great measure sacrificed the utility of many original and enlightened views to the fond conceit of a new, and in some instances an incomprehensible, nomenclature.

The skill of Fabricius as an entomologist has never been surpassed, and it is therefore the more to be regretted that he should have been influenced in the formation of his system by other motives than a desire to perceive and point out the truth. But it is known that he was swayed as much by the ambitious hope of founding a new doctrine, of which he destined himself to be the oracle, as by the desire of proceeding directly in the path of nature. Hence his avowed enmity to the eclectic system of Latreille, which, during the opening career of that celebrated entomologist, he declared it to be his intention utterly to destroy. Yet the system of Latreille not only stands, but, when viewed in relation to the application of its general principles, has in a great measure superseded that of Fabricius. At the same time, the accurate discrimination and extensive knowledge of the latter, and the wide circle which his system embraces in detail, render it still indispensable for a knowledge of the species.

Illiger died young. His talents were such as to raise among his compatriots the highest hopes of his future eminence, and his death was a subject of just regret to all who knew what he had achieved so well at an early age, and who the more gladly lent themselves to the anticipation of what he would afterwards have accomplished had his life been prolonged. Of his classification it has been written by a competent judge: “Neque apud veterem, neque apud recentiorem quendam auctorem ullum systema invenerim, quod, tam sua perspicuitate, quam accuratione, Illigeriano magis commendari mihi videatur.” Many of his genera arc indeed remarkable for their felicitous construction and consonance with the natural arrangement. They have in consequence been readily adopted by his more fortunate fellow-labourers in the same field, in whose works they will remain, and be handed down in ample attestation of the author’s genius; but the system itself will suffer a partition, and ere long cease to be practically known under the form in which it was originally promulgated, and this mainly in consequence of his having adopted so many new names.

Μ. de Blainville is still alive, and the longer he lives the better for the sciences of anatomy and physiology, neither of which contains in its modern annals the name of a more accomplished or enlightened expounder of its mysteries than his own; but in the character of a naturalist, and in connection with the subject of nomenclature, he unfortunately sins more than all his predecessors. He really miscalls the objects of zoology most sadly, yet his knowledge of the essential bases of the science is no doubt too profound to admit of his applying it without new and important results. Hence the pity that these should not at all times be stated in such terms as not only to amalgamate more closely with the kindred labours of his contemporaries, but to fall rather more clearly within the comprehension of ordinary minds.

As it is not our intention in the present rapid sketch to enter into the distribution of the animal kingdom beyond the greater divisions called classes, we shall not exhibit the systems of the two first-named authors further than to say, that the former attended almost exclusively to entomology, the latter chiefly to the mammalia and birds. ∖∖ hen we come to the divisions of our subject under their separate heads, tabular views or more detailed analyses[7:3:171] will be presented of the labours of these and other ingenious inquirers of the past and present times.

We have said that we regarded the system of Linnaeus is the basis of all those by which it has been succeeded, and that without a knowledge of his classification it would be impossible to understand either the merits or defects of more recent systems. We shall therefore here present the classes into which the great Swedish naturalist divides the animal kingdom.
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It may be observed, that the deservedly popular system of Linnaeus, though it does not profess to be a natural nethod of classification, actually is so in many of its parts; nor can it be denied that, on the whole, it usually brings together as many groups of natural genera as occur in most systems that have been promulgated, especially if we take into consideration the period at which it was composed, and the comparatively scanty materials within his reach. Linnaeus was probably aware of the extreme difficulty, we might say at once of the utter impossibility, of a perfectly natural arrangement; for he confesses, in his Philosophia Botanica, his inability to define the great divisions called orders, on account of their being so connected with each other by various points of affinity, as to form a map rather than a linear series; and the observation may be applied with equal truth to the subjects of the animal kingdom. In regard to the excellence of his genera themselves, their consonance with nature is rendered still more evident, by the great proportion of those which Cuvier and Latreille have retained as leading generic divisions in their recent works,—certainly the most skilful approaches which have yet been made in the establishment of a natural system. It has been asserted, and we believe with truth, that such naturalists as are perpetually intent on the abstract theory of classification, rarely attain the highest excellence in the discrimination or definition of the species,—the only distinctions possibly which have a real foundation in nature, and upon an accurate and extensive knowledge of which alone their theoretical systems can be substantially and permanently built. At all events, it is admitted that Linnaeus is a guide almost infallible, in as far as concerns his wonderful facility in discovering the minor natural groups. If he could have combined these as well as he has defined them, his possession of the sceptre would have been still undoubted.^[21. Horae Entomologicae, part ii. p. 428. ]

Μ. Virey, in the first edition (1803) of the Nouveau Dictionnaire d’ Histoire Naturelle, divides the animal kingdom into three great tribes, in accordance with the nature and distribution of the nervous system. As he appears to have been among the first to attribute a due degree of importance to that system in the classification of animals, we shall here exhibit a view of his general arrangement.
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The following summary will serve to illustrate Μ. Virey’s views of the nature and characteristics of these three great divisions. We commence with the zoophysical tribe.

1st, Zoophytes are distinguished by an organic tissue of a very soft and pulpy nature, more or less diaphanous, and very contractile, though we cannot readily perceive its muscular fibres. Its fundamental character consists in the extreme division of its nervous molecules throughout the flesh of these animals. Except in the Echinodermata and some other radiated classes, we can scarcely assert the existence of a nervous system amongst them (on which account they are named apathiques by Lamarck). Each portion of the body having its nervous molecule and its particular[7:3:172] source of vitality, there is no common centre of sensation; thus division and generation are almost synonymous, and when individual parts are mutilated they are speedily reproduced. With these tribes the production of the species is in fact nothing more than a simple sprouting of a bud or offset, which separates itself from the maternal stalk. Zoophytical animals are of no sex, and thus resemble the agamous vegetables. The mouth is usually placed in the centre of the body, and is frequently surrounded by a species of unarticulated arms, radiating from a centre like the petals of many flowers. Several genera have only a single opening for the reception and rejection of the aliment. They have no viscera (excepting caeca in certain species); no heart, nor arterial nor venous vessels; no true circulation; no apparent organs of respiration. They are all aquatic, and water Seems indeed the only fluid which pervades their economy. They may be called the cryptogamia of the animal kingdom. The sense of touch, and perhaps that of taste, seem the only ones enjoyed by these animals.

2dly, The Invertebrata present a greater complication of organs. Their principal character consists in a nervous system, extending itself, especially in the intestinal cavity, by numerous ramifications. In all the families of this great tribe, the nervous trunks surround the oesophagus, pass beneath the belly, and are furnished with many ganglions which supply branches to the different organs. That which is regarded as the brain in this tribe (named sensible by Lamarck) is nothing more than one or two ganglia situated above the oesophagus; but the particular distribution of the two nervous branches which spring from the collar of the gullet, and extend themselves over the body, gives rise to the divisions of molluscous and articulated animals established by Cuvier.

The last-named naturalist has observed, that in the mollusea the nervous system is composed of many ganglionic masses, dispersed throughout the organization, but connected by means of nervous filaments; and that the chief of these masses constitutes a kind of brain above the oesophagus. The mollusea have no skeleton; their muscles are attached to the skin, a soft contractile envelope, in which in many species are produced shells, or stony bodies of calcareous carbonate, formed by exudation or superimposed concretion. Besides the sense of touch, common to all animals, the mollusea are gifted with that of taste, and sometimes of sight; but the sense of hearing has not been remarked, except among the Cephalopoda or cuttle-fish. Their systems of digestion and secretion are rather complex; they are provided with a liver, and possess a circulating or vascular system, through which flows a humour or whitish sanies in place of blood. Their respiration is effected by aquatic or aerial branchiae. The sexual organs are frequently united in the same individual.

Among the articulated classes (such as the Crustacea, the arachnides, and insects) the nervous system consists of a double chord, extending from the head to the posterior extremity, and bearing knots or ganglia which correspond to the segments of the animal’s body. The first ganglion above the oesophagus takes the place of what we call the brain in the higher animals, but it is not voluminous in proportion. All these animals are composed of segments or annular divisions, and their forms are elongated, and more or less cylindrical. Their skin or outer covering, always of a somewhat solid texture, becomes in many families hard, corneous, or even stony; and the muscles are attached to its interior. The greater number have articulated members, feet, wings, pmcers, palpi, &c. Many of these animals have closed vessels; and the Crustacea have a heart and branchiae. Others, according to Cuvier are nourished by simple imbibition. Those insects which undergo metamorphoses are furnished with tracheae or air-vessels for respiration, dispersed over their bodies. The organs of the sense of hearing are not discernible except among the Crustacea; taste is universal, and also sight, except among the worms. Their jaws always ply laterally. The sexual organs are usually separate.

3dly, The Vertebrata comprehend all those animals which have a nervous system composed of ganglia, called sympathetic, for the functions of the internal life; and another symmetrical nervous system, of which the principal portions are inclosed in the cranium and spinal column, and which sends off chords for the functions of the external life. These are the most perfect and most highly endowed of all animals; they are named intelligens by Lamarck, and they are always endowed with five senses, of which never fewer than four are situated in the head. They possess a heart, red blood, a liver, lungs in the species which live in air, and branchiae in those which live in water. An articulated, bony, symmetrical skeleton, placed in the interior of the body, gives support and solidity to the different parts. Such are man, mammiferous animals, and birds, which have warm blood, and respire by cellular lungs; such also are reptiles and fishes, of which the blood is cold. In all, the mouth has two horizontal jaws, and the members are never more than four in number.

The preceding are Μ. Virey’s views of the distribution and general characteristics of the different classes of the animal kingdom.^[22. Moeurs et Instinct des Animaux, tome i. p. 180. ] They contain a sound exposition of several of the substantial relations which exist between the different systems of the animal economy, and we present them to the reader even at the risk of afterwards repeating in part several essentialities of his doctrine, when we come to promulgate the views of his celebrated countryman and contemporary Baron Cuvier.

We shall next present a tabular view of the general distribution and primary divisions of animals according to the system of Lamarck. It will be observed that this author commences with the lowest tribes.
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The author of the preceding arrangement has entered upon the discussion of certain preliminary points connected with the subject of classification, which maybe regarded as composing the art rather than the science of Zoology. He inquires (in his introduction to the Hist. Nat. des Anim. sans Vert.) what are the operations to be performed for the execution of a good distribution of animals, and for the establishment of the necessary divisions of that distribution? These operations he states to be as follows: lst, To assemble animals together according to a principle which is not arbitrary, and so as to form a geneeral series, whether simple or ramified: 2dly, To divide this general series into different kinds of lesser divisions, of which the one shall be subordinate to the other; and with that view to make choice of and submit to certain suitable and convenient principles (principes de conveance): 3dly, To fix the rank of each sort of division after one general principle, previously established; as, for example,

The rank of each primary group in the total series;

That of the classical divisions of each primary group;

That of the orders or families in each class;

That of the genera in each family; and

That of the species in each genus.

The execution of these three sorts of operations is regarded by Lamarck as indispensable; and that it is so has been long felt by naturalists, almost all of whom have more or less occupied themselves in the attempt, but always in an arbitrary manner—that is to say, without the previous establishment of principles deserving of general consent. The first of the operations alluded to—that which concerns the bringing together of species in such a manner as to form a general series—is an essential preparation, which ought to precede the other operations, and without which indeed the latter could not be executed. It tends, moreover, to enable us to discover the order of nature, with which it is so highly important that we should become acquainted. Although nature has necessarily followed a certain order in the formation of organized beings, and especially of animals, yet as she has now dispersed these animals, and commingled all the different races over the surface of the solid globe, or through the wide depth of liquid waters, the original order of formation is to a certain extent disfigured, and so far imperceptible. We are therefore obliged, with a view to its ascertainment, to search after some means by which we may attain to that discovery, and to work out some solid principles to lessen the chance of error. In regard to this, the most important step has been already attained, when we acknowledge the interest inspired by affinities or relations, and the necessity of understanding these, with a view to submit to them, as to a test, the various parts of our general distribution. It may thus be perceived, that in order to establish a good distribution of animals, in such a manner that its solidity shall run no risk of being enfeebled by the arbitrary nature of opinion, it is necessary first of all to assemble our species according to well-determined affinities; after which we may, without inconvenience, trace out the lines of demarcation which separate the groups called classes, and those other subordinate groups of which the establishment is so advantageous, provided the natural dations are in nowise compromised by their formation. It may perhaps be proper shortly to inquire into the nature of these relations, their different degrees, and the exact uses which it becomes us to make of such as we ascertain and acknowledge. We shall then be enabled with greater facility to determine the principles which it is fit to establish.

Relations, according to Lamarck, are those traits of resemblance or analogy which nature has bestowed, as well on her different productions when compared among themselves, as on the different parts of those same productions when compared with each other. These traits of resemblance and affinity are so necessary to be known and understood, that no methodical distribution can be established on a sure foundation, if the objects which it embraces are not arranged according to the law which they prescribe. Relations are of different orders, some being very general, others less so, and many altogether special or particular. Moreover, although, in general, relations belong to nature, all are not the direct result of her operations in regard to her productions; for among the relations which we perceive between the compared parts of different beings, there are many which result merely from a modifying cause. Thus the relations of exterior form, which are so apparent between the cetacea and fishes, can only be attributed to a property resulting from the dense medium which each inhabits, and not to any direct plan in the operations of nature in regard to both. It is necessary then carefully to distinguish those obvious and acknowledged relations which pertain to the direct operations of nature in the progressive organization of animal life, from certain others, equally obvious and acknowledged, which result from the influence of local circumstances, or from the peculiar habits which different races have in some instances been forced to acquire.

Relations of the last-named nature, though certainly of greatly inferior value to the former, are by no means limited in their influence and exhibition to external characters alone; for it may be demonstrated that the external cause which possesses the power to modify the direct operations of nature frequently exercises an obvious influence on several internal organs. It becomes the more necessary then to establish certain rules, devoid of arbitrary qualities, to enable us justly to appreciate the nature and value of these relations; and it may be established as a principle in zoology, that it is from the interior organization that the most essential are to be obtained. This principle is well founded if it expresses the pre-eminence which ought to be accorded to general considerations, gathered from the interior organization, over those derived from external parts. But if, instead of using it in this manner, we apply it to particular cases of our own choosing, and without pre-established rule, it is capable of great abuse; and we shall arbitrarily assign to relations presented by such or such system of internal organs, a preference over certain others, although the relations of the latter may in reality be of greater importance. By this means, sufficiently convenient for the changeable views of individual authors, we admit into various parts of our distribution inversions in every way contrary to the order of nature.

It is true, as has been already observed, that a cause which modifies organization not only acts on the exterior parts of animals, but also produces various modifications in their internal structure. It follows, that it is incorrect to suppose that the relations which exist between the races, and especially between the genera, the families, the orders, or even in certain cases the classes of animals, can always be decided merely from the isolated consideration of any internal organ, arbitrarily selected. On the contrary, Lamarck is of opinion that the relations of which we speak cannot be suitably determined except by a consideration and comparison of the whole of the interior organization, and, auxiliary, by that of certain special internal organs which assured principles have demonstrated to be the most preferable and important.

The second question proposed by Μ. Lamarck is the following: What are the principles by which we ought to be guided in our operations, so as to exclude from these [7:3:174]whatever is arbitrary? Our author is of opinion that it is • by the precise discrimination of each sort of relationship, 'and by aid of a determination, substantial and explained, of the preference which ought to be accorded to one kind over another, that we shall discover principles proper to regulate all the parts of our general distribution of animals. It is necessary then to determine the principal kinds of relations which ought to be employed to attain this end, and then to fix the superiority in value which one kind possesses over another. The following is the classification of Lamarck in further illustration of this subject.

* Relations between Comparative Organizations, deduced from the whole of their parts.

These relations, though general, manifest themselves in different degrees, according as we seek for them among races compared in themselves, or among groups of animals of different races compared with each other. It is necessary then to distinguish several kinds.

First kind of general relations. — These seem immediately to connect races or species with each other. 1hey are of necessity the first, because it is they which furnish the greatest of the relations between animals which differ from each other. The zoologist who determines it, taking into consideration all the parts of organization, as well interior as exterior, admits not of this sort of relation, unless when it presents the smallest and least important difference. We know that animals which resemble each other perfectly, both in their internal and external organization, can be nothing more than individuals of the same species. In this case the relation is not considered, as such animals offer no distinction. But those which present among themselves a difference, tangible, constant, and at the same time the smallest possible, are connected by the greatest and most immediate of relations, if they present elsewhere a great resemblance in all the parts of their interior organization, as well as in the greater proportion of their external features. And this sort of relation does not demand a consideration of the degree of composition or relative perfection of the animal organization, for it determines itself in all the ranks of the scale. It is so easy to seize, that every one acknowledges it at first sight; and it is by employing it that naturalists have formed those smaller portions of the general series called genera, notwithstanding the arbitrary nature of their limits. Thus, in this first kind of relation, which may be called the relation of species, the difference between the objects compared is the smallest possible, and need only be sought for in the particularities of form or of the external parts of individuals.

Second kind of general relations. — This embraces the agreements which exist between groups of different animals when compared together. It may be named the relation of groups; and, to acquire a knowledge of its nature, we must no longer occupy ourselves essentially with the particulars of the general form, nor with those of the external parts, but almost solely with the interior organization, considered in all its parts. It is this kind chiefly which ought to furnish the differences by which we distinguish the groups from each other; and it is inferior in one or more degrees to the first kind in the quantity of resemblances which exist between the compared objects. It serves to form the families, by connecting the genera with each other; to institute the orders, or the sections of the orders, by uniting several families; and, lastly, it determines the classical groups into which we ought to partition the general series. The relations of which we now speak cannot, however, be employed to determine the rank of the great masses of that series, but only to form diverse combinations for establishing and distinguishing these masses.

From the consideration of these relations, the two fol. lowing principles may be deduced.

First principle.· —The general relations of the second kind do not require a perfect resemblance in the interior organization of the compared animals. “Ils exigent sculement que les masses rapprochées se ressemblent p] us entr’elles, sous ce point de vue, qu’elles ne le pourraient avec aucune autre.” (Anim. sans Vert, tome i. p. 355.)

Second principle. — The greater and more general ft e compared masses, the more will such masses differ in their internal structure. Thus the families present a less difference in the interior organization of the animals by which they are constituted, than the orders or classes. Third kind of general relations. — We may denominate relations of rank those which serve to determine the position in the great series, and which, proceeding from a fixed point of comparison, effectively show among the compared objects a relation, whether great or small, in the composition or perfection of the organization. This kind is obtained by comparing any organization whatever, taken in the totality of its parts, with any other given Organization which may be presented as a point of departure or of comparison. It is then determined, by the resemblance, greater or less, which is found between the two compared structures, to what extent that which we compare departs from or approaches to that which is given as a point of comparison. We shall see that this sort of relation is the only one which ought to serve for regulating the rank of all those important primary masses into which we divide the animal kingdom.

If we consider the question concerning the choice of a particular organization, from or towards which to remove or approximate other organizations successively, according to their greater or less resemblance, it becomes evident that the selection ought to fall on one or other extremity of the animal kingdom (as in that case there would be no uncertain balancing), and the best known extremity should have the preference. Thus, in setting out from the most perfect and highly finished structure, we should, in the determination of all the ranks, proceed from the most composite to the most simple, and should close the series by the most imperfect and least organized of the whole.

Of all forms of structure, that of man, considered in its totality, is at once the most composite and complete. From this Μ. Lamarck concludes that the more any animal organization approaches that of the human race, the more it advances towards comparative perfection and its own completion. This being the case, the organization of man is with that author the point of comparison and departure from which to judge of the relation, whether near or distant, of every form of animal structure, and by which we are to determine the rank which those forms, or the groups which they constitute, ought to occupy in the general series. The organization alluded to, considered in the totality of its parts, furnishes the means by which to judge of the degree of composition and perfection of other animal structures also regarded in their totality. And in doubtful cases it is not difficult to rid ourselves of uncertainty and embarrassment, by having recourse to the fourth kind of relations, or to those principles which concern the comparison of the different organs separately considered, and establish a predominating value and influence among certain of those organs when compared with others. Thus, our point of departure or comparison being found, the rank of all the divisions may be assigned with facility by the aid of the principles which follow.
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First principle. — For the determination of the rank of each mass in the series,—the most complicated and complete of animal organizations being selected as the point of comparison,—the more another form of animal structure considered in the whole of its parts, resembles that of the fore-chosen, the more it will approximate towards it by its relations; and reciprocally in the converse cases.

Second principle. — Among the organizations of which the plans are different from that which comprehends the particular structure selected as the point of comparison, those which offer one or more systems of organs similar or analogous to such as form a portion of that with which they are compared, shall rank superior to those possessed of a smaller number of these organs, and, a fortiori, to those in which they are wanting.

With the assistance of the three kinds of relations above indicated, and the principles deducible from them, Μ. Lamarck regards it as easy to determine the distinctions of species, and those of the various larger groups which species form; and to decide, in a manner by no means arbitrary, the rank and station of each group in the great series. If this be true, the science will cease to be as vacillating in its onward march as it has hitherto proved.

But our efforts would be incomplete, and would still leave too large a field for the exercise of arbitrary opinions, if no attempt were made to establish and define the value of particular relations, — that is to say, of those which are obtained by the comparison of particular internal organs, considered in an isolated manner in different animals.

** Relations between similar or analogous parts taken separately in the organization of different animals, and compared with each other.

The fourth kind of general relations merely embraces particular relations between unmodified parts. It is drawn from the comparison of parts separately considered, and which, in the system of organization to which they belong, offer no real anomaly. The consideration of this kind is sometimes of great consequence in assisting to decide in doubtful cases, when we arc anxious to determine, among certain compared groups, to which the superiority of rank ought to be assigned. Such cases sometimes occur where the whole of the parts of the interior organization present no means of deciding, in an unarbitrary manner, to which of two organizations the superiority belongs. It is especially in the formation and position of the orders, sections, families, and even genera, of each class, and consequently in the assignment of the rank of all these inferior groups, that the employment of this fourth kind of relations is of advantage; because, in regard to such groups, the principle of the third sort of relations is frequently very difficult of application; and thus arbitrary modes of arrangement are introduced, most baneful to the science, by exposing the works of naturalists to a continual variation in the determination of the relations which ought to fix the imposition of the groups, and their order of position. In fact, as many animals, really connected by the general characters of their class, present remarkable differences in certain of their interior organs, and yet at the same time exhibit equally striking resemblances in others, we feel that, in order to appreciate the degree of importance possessed by the relations which exist between particular organs, we must have recourse to certain regulating principles in our determinations, to avoid arbitrary conclusions. The two following principles arc proposed by Lamarck, to enable us to appreciate the relations observable between particular internal organs in different animals compared with each other.

First principle. —Between two internal organs, or systems of internal organs, separately considered and compared, that of which nature has made the most general employment ought to have the pre-eminence assigned it in the value of the relations which it presents. According to this principle, the following is the order of importance which we ought to attribute to the particular organs which nature has employed in the interior organization of animals :—

The organs of digestion; The organs of production; The organs of respiration; The organs of sensation; The organs of movement; The organs of circulation.

Thus, when we take into view the greatest generality of employment of the particular organs of which nature makes use in the interior organization of animals, we perceive that the organs of digestion occupy the foremost rank,—those of circulation the last. We have thus an order of value or precedence, in regard to these important organs, capable of regulating, in doubtful cases, the preference which one relation merits over another.

Second principle. — Between two different modes of the same organ, or system of organs, that which is most analogous to the mode employed in a superior or more composite and complete organization, merits the preference in the relations which it exhibits. If, for example, we desire to employ a relation afforded by the organs of respiration,— to judge of the preference which it deserves over that offered by other organs,—we arc obliged, according to the principle above established, to keep in view the following consideration :—Although the system of organs provided for respiration is very widely employed in the organization of animals, since, with the exception of the polyped and infusorial classes, all the rest possess a respiratory system, yet the mode of that system not being the same in all the classes by which it is exercised, we assign a higher value to the true lung than to the branchia, to the latter than to the acriferous tracheae, and to these than to the aquiferous tracheae. According to this view, we may judge whether the mode of respiratory organs of which we wish to employ the relation, is sufficiently high in value to per mit our yielding to it a preference over a relation deduced from some other kind of organs.

The fifth kind of relations embraces the particular relations observable between the modified parts. It requires that, among the parts compared, we should discriminate between that which is due to the real plan of nature, and that which pertains to the modifications which that plan has experienced from accidental causes. Thus this class of relations is derived from parts which, considered separately in different animals, arc not in the state in which they ought to be, according to the plan of organization to which they belong. To judge of the degree of importance which ought to be accorded to a relation, and the preference which it deserves over another, it is a matter of no slight consequence to distinguish if the form, the increased or diminished development, or even the entire disappearance of the particular organs under consideration, belongs to the plan of organization of the animals subjected to such modifications; or whether the state of these organs is not rather produced by a modifying and determinable cause, which has altered or annihilated that which nature had executed, and would have maintained, but for the influence of that later cause. “For example,” says' Lamarck, “it would have been impossible for nature to furnish a head to the infusoria, the polypi, or the radiata, &c.; for the condition of these bodies, and the degree of their organization, did not permit it; and it was only on arriving at the class of insects that a genuine head could be supplied.” Now, as nature never retrogrades in her operations, we naturally expect, that when once arrived at the formation of insects, and consequently of heads, the recipients of the special senses, all animal organizations [7:3:176]superior in composition to that of insects will also exhibit these organs. This, however, is not universally the ease; because no distinct head is observable among the annelmes, the cirrhipedes, and many mollusea, all of which are generally regarded as superior to the class of insects. U - lιe cause étrangère à la nature, en un mot, one cause modifiante et déterminable, s’est done opposée à ce que les animaux cités soient pourvus d’une véritable tête.” (Anini. sans Vert, tome i. p. 363.) And that cause appears to have operated sometimes by hindering to a greater or less extent the development of that part of the body, and at other times by effecting its complete destruction. We find the same thing in regard to eyes and teeth, and to various other parts both of the internal and external structure; because a modifying cause has had the power to alter, enlarge, diminish, or even to effect the total disappearance of these organs. We may perceive, then, that the relations obtained from the considération of changed or modified parts must be of very inferior value to those furnished by the same parts existing in a state conformable to the plan of nature. Hence results the following Principle. — Whatever nature has directly formed deserves a pre-eminence in value over that produced by a fortuitous cause, which has modified the work of nature; and in the choice of a relation to be employed, we should assign the preference to every organ, or system of organs, which we find existing as it ought to do according to the plan of organization of which it forms a part, over that organ, or that system of organs, of which either the condition or existence has resulted from a modifying cause, extraneous to original nature.

When two different organs, between which a choice is to be made, are both found to be changed or altered by a modifying cause, the preference should be given to that which is least removed by such a modification from the condition in which it would have existed according to the plan of organization of which it formed a part.

The third question proposed by Μ. Lamarck is as follow’s :—What disposition or mode of arrangement should be given to the general distribution of animals, so as to render it conformable to the order followed by nature in the production of these beings? To resolve this question, we must also endeavour to deduce some principle from nature herself, with a view to such conformity; for if we were to determine the general distribution of animals according to the progression which exists in the animal organization, it appears that we might, in that progression, proceed with as much reason from the most composite to the most simple, as from the most simple to the most composite. Such a proceeding, however, could not rest on a proper basis; for we shall find that nature, consulted in the order of her operations in regard to animals, indicates the following principle, which excludes all arbitrary selection:— Nature always operating in a gradual manner, and consequently never producing animals otherwise than successively, has obviously proceeded in swh a production from the most simple towards the most complex. We ought, therefore, in our general distribution, to imitate the order which nature herself has followed. “J’ai, en effet, montré,” says Lamarck, “dans ma Philosophie Zoologiq ut (tome i. p. 269), que, pour rendre la distribution générale des animaux conforme à l’ordre qu’a suivi la nature en' produisant toutes les races qui existent, il fallait procéder du plus simple vers le plus composé,—c’est-à-dire, qu’il était nécessaire de commencer cette distribution par les plus imparfaits des animaux, et les plus simples en organisation, afin de la terminer par les plus parfaits, par ceux qui ont l’organisation la plus composée.” He further observes, in his Anim. sans Vert. “Cet ordre est le seul qui soit naturel, instructif pour nous, favorable à nos études de la nature; et qui puisse, en outre, nous faire connoitre la marche de cette dernière, ses moyens, et les lois qui régissent ses opérations à leur égard.” Although we may find it less pleasant or conformable to our habitual taste to present at the head of the animal kingdom creatures of the most limited perceptions, excessively minute in size, and of scarcely any consistence in their parts,— yet as in all things it is necessary to consider the end in view, and the means which conduct towards it, Lamarck is of opinion that the arrangement established by usage in the distribution of animals is precisely that which leads us away from the point in view, as well as the least favourable for our instruction, and that it opposes the greatest number of obstacles in the way of our perceiving the plan, the order, and the means employed by nature in her operations concerning the animal world.

If in the study and examination of living bodies we had no other object in view than to distinguish the one from the other by characters deduced from their external forms—and if we were not desirous to regard their various and wonderful faculties otherwise than as simple matters of amusement, not altogether unfitted to excite the curiosity of a leisure hour—then the most ordinary and arti∙ ficial system would suffice; for in that case it would be useless to occupy ourselves with researches concerning the affinities of animals, or to study their internal structure. But all naturalists are now agreed regarding the high importance of these affinities, and the necessity of holding them ever in view in our general arrangement of the animal kingdom. The ’ bat is no longer classed with birds merely because, like them, it wings its way through the air; nor are seals or whales regarded as fishes because the dense nature of the medium which they inhabit requires a somewhat analogous form; neither are cuttlefish and polypi confounded together, though the mouth of each is surrounded by numerous arms.

We have dwelt at greater length than we intended on the system of Lamarck, or rather on the views by which he seeks to illustrate the principles on which his system professes to be built. Though occasionally prolix, and sometimes rather obscure, his observations, on the whole, are well deserving of an attentive consideration. Like most of his countrymen, he is unfortunately more regardful of secondary causes, and more anxious to illustrate their fitness and sufficiency, than he is ready to acknowledge the source from which they spring, or to admire the wisdom and beneficence of their providential institution.^[23. "The doctrine of Epicurus, that the Deity concerns not himself with the affairs of the world or its inhabitants, which, as Cicero has judiciously observed {De Nat. Deor. lib. i. ad calcem), while it acknowledges a God in words, denies him in reality, has furnished the original stock upon which most of these bitter fruits of modern infidelity are grafted. Nature, in the eyes of a large proportion of the enemies of revelation, occupies the place, and does the work, of its great Author. Thus Hume, when he writes against miracles, appears to think that the Deity has delegated some or all of his powers to nature, and will not interfere with that trust ( Essays, ii. 75); and, to name no more, Lamarck, treading in some measure in the steps of Robinet (who supposes that all the links of the animal kingdom, in which nature gradually ascends from low to high, were experiments in her progress towards her great and ultimate aim, the formation of man—Barclay on Organization, &c. 263), thus states his opinion:—“L a nature, dans toutes ses operations, ne pouvant procéder que graduellement, n a pu produire tous les animaux à la fois; elle d’abord n’a formé que les plus simples! et passant de ceux-ci jusques aux plus composes, elle a établi successivement en eux différens systèmes d’organes particuliers, les a multipliés, en a augmenté de plus en plus l’énergie, et les cumulant dans les plus parfaits, elle a fait exister tous les animaux connus avec l’organisation et les facultés que nous leur observons.” (Anim. sans Vertèbr. i. 123.) Thus denying to the Creator the glory of forming those works of creation, the animal and vegetable kingdom (for he assigns to both the same origin, ibid. 83), in which his glorious attributes are most conspicuously manifested; and ascribing them to nature, or a certain order of things, as he defines it (214)— a blind power, that operates necessarily (311), which he admits, however, to be the product of the will of the Supreme Being (216). It is remarkable, that in his earlier works, in which he broaches a similar opinion, we find no mention of a Supreme Being. (See his système des Animaux sans Vertèbres; Discours d’Ouverture.) Thus we may say, that, like his forerunner Epicurus, Re tollit, dum oratione relinquit Deum. But though he ascribes all to nature, yet, as the immediate cause of all the animal forms, he refers to the local circumstances, wants, and habits of individual animals themselves; these he regards as the modifiers of their organization and structure (162). To show the absurd nonplus to which this his favourite theory has reduced him, it will onlv be necessary to mention the individual instances which, in different works, he adduces to exemplify it. In his Système he supposes that the webfooted birds (Anseres) acquir∙ ed their natatory feet by frequently separating their toes as far as possible from each other in their efforts to swim. Thus the skin that unites these,toes at their base contracted, a habit of stretching itself; and thus in time the web-foot of the duck and the goose was produced. The waders (Grallae), which, in order to procure their food, must stand in the water, but do not love to swim, from their constant efforts to keep their bodies from submersion, were in the habit of always stretching their leθ ’ s with this view, till they grew long enough to spare them the trouble! !! (13). How the poor birds escaped drowning before they had got their web-feet and long legs the author does not inform us. In another work, which I have not now by me, I recollect he attributes the long neck of the came opard to its efforts to reach the boughs of the mimosa, which, after the lapse of a few thousand years, it at length ac-comphshed. . . In his last work he selects as an example one of the Moluscoe, which, as it moved along, felt an inclination toex- ι plore by means of touch the bodies in its path: for this purpose it caused the nervous and other fluids to move in masses successively to certain points of its head, and thus in process of time it acquired its horns or tentacula!! (Anìm. sans Vertèbr. i. 188.) It« grievous that this eminent zoologist, who in other respects stands at the head of his science, should patronize notions so confessedly absurd and childish. (Introduction to Entomology, by Kirby and Spence, vol. iii. p. 349 ) ]
[7:3:177]

We shall now proceed to the system of another naturalist, also highly accomplished in the science, Μ. Duneril the friend and pupil of Baron Cuvier, and to whose collection of the oral demonstrations of his great master we were originally indebted for the publication of the Leçons d’ Anatomie Comparée.
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The ensuing tabular view exhibits the classification proposed by Μ. de Blainville. We shall leave the reader o judge for himself of the propriety of introducing so many new appellations for groups constructed long ago. His nomenclature is no doubt intimately connected with his views of the structure and physiology of animals, and is highly approved of and adopted by many competent judges of the science.
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Let us here note, that Μ. Desmoulins, in the 2d edition of Dr Magendie’s Physiology (1825), has exhibited a ' system in which the principles of Cuvier and De Blam-ville are joined in one.

A learned and ingenious Scotsman, Mr William Sharpe Macleay, is the author of several profound and original views in natural history. The unbroken and continuous succession, or linear series, in which systematic writers had previously regarded the objects of their contemplation, was first deviated from by Lamarck, who, m his supplement to the first volume of his Animaux sans Vertèbres, presented the Invertebrata in a double subramose seriesi consisting of articulated and inarticulated animals. The following are the principal bases of Mr Macleay’s system.^[24. See Horoe Entomologicoe, and Kirby & Spence’s Introduction to Entomology vol iii p 12 ].

1. That all natural groups, whether kingdoms or any subdivision of them, return into themselves; a distribution which Mr Macleay expresses by circles.

2. That each of these circles is formed precisely of five groups, each of which is resolvable into five other smaller groups, and so on till we reach the extreme term of such division.

3. That proximate circles or larger groups are connected by the intervention of lesser groups, denominated osculant.

4. That there are relations of analogy between the corresponding points of contiguous circles.

The author has represented his system by tables of circles, inscribed with the names of the five primary divisions of each group. The following table exhibits his general view of the animal and vegetable kingdoms;

It will be perceived by the preceding diagram, that Mr Macleay divides the animal kingdom into five great subkingdoms, viz.

1. Acrita, composed of the infusoria, the polypi, the corallines, the taeniae, and the least organized of the intestinal worms.

2. Radiata, containing medusae, star-fish, sea-urchins or echini, and others.

3. Annulosa, consisting of insecta, arachnida, and Crustacea.

4. Vertebrata, constituted by beasts, birds, reptile, amphibia, and fishes.

5. Mollusea, including the numerous tribes of shell, fish or marine testacea, fresh-water shells, snails, slugs, & c . which, from the analogies presented by their soft or mucous substance, the peculiarities of their nervous system, and the general imperfection of their senses, appear as it were to return again to the acrita, though allied to the vertebrata by characters drawn from the possession of a heart and a circulating system.

The ensuing set of circles exhibits the further subdivision of the five sub-kingdoms into classes.

The osculant classes are such as are placed between the circles. In the molluscous circle two classes are still wanting to complete the quinary arrangement of that great division. According to Mr Kirby, the number foe, assumed by Mr Macleay as a principal basis of his system, and as consecrated in nature, ought to yield to the number seven, which is consecrated both in nature and scripture. Metaphysicians enumerate seven principal operations of the mind, musicians seven principal tones, and opticians seven primary colours. In scripture, the abstract idea of this number is, completion, fullness, perfection. Mr Kirby seems to think that Mr Macleay’s quinaries maybe found resolvable into septenaries, in consequence of future investigations.^[25. Introduction ⅛ Entomology, vol. iii. p 15. The quinary system, in its application ‘to insects and other annulose animals, h pretty fully developed by its ingenious author in his Horoe Entomologicae, already more than once referred to. An excellent paper by ìheLŉuioean Society ° assificatl ° n of birds > 111 accordance with the same system, will be found in the 14th volume of the Transactions of ]

We shall enter at greater length into a detailed exposition[7:3:179] of the quinary system of arrangement under the articles Entomology and Ornithology.

Cuvier divides the animal kingdom into four principal branches. Setting aside all accessory and artificial characters, he proceeds upon the consideration of the essential structure of animals, and thus deduces four great Groups or separate types of form, to one or other of which all the minor divisions may be ultimately referred.

In the first of these forms the brain, and the great cenral trunk of the nervous system called the spinal marrow, are protected by strong bony coverings—the cranium and vertebral column. To the sides of that column are attached the ribs and the bones of the anterior and posterior members. All the classes of this primary division are provided with red blood, a muscular heart, a mouth with two horizontal jaws, and special organs of vision, hearing, taste, and smell, placed in the head or upper and anterior portion. They have never more than four members; their sexes are always separate; and they nearly resemble each >ther in the distribution of their medullary masses, and the principal branches of their nervous system. On examining more narrowly the constituent parts of the classes which compose this great assemblage, it is easy to discover many striking analogies both of form and structure, even in those groups which are most distantly related to each other; and from the human species to the last of the fishes there exists an obvious conformity to the same general plan. The name of Vertebrated Animals is bestowed on this division, on account of their being possessed of a vertebral column or back-bone. The following are the principal groups or classes into which it is further divisible.
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The second great division possesses no skeleton. The muscles are attached to the skin, which forms a soft contractile envelope; and many of the species are protected by hard coverings, commonly called shells, which are supposed to occupy in the cutaneous system of this form of animal life the same station as the mucous membrane of the preceding division. The nervous system is contained along with the visecra within this general envelope, and îs composed of many dispersed portions, of which the principal, placed above the oesophagus, may be regarded as representing the brain. Of the four special senses it is impossible to discover the organs of more than two, taste and sight; and even of these the last is frequently wanting. The organs of hearing are visible only in one family. The system of circulation is however complete; there are particular organs for the performance of respiration; and the functions of digestion and secretion are almost as complicated as in the vertebrated classes. The subdivisions of this second form are called Molluscous Animals ; and although the external configuration of their parts does not exhibit the same agreement as that of the vertebrated classes, there is always a corresponding resemblance in their essential structure and functions. The following are the classes of this branch of the animal kingdom.
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The third great preponderating form is represented by insects and other analogous classes. Their nervous system consists of two long ventral or sublateral chords, which swell out at intervals into knots or ganglia. The first of these ganglia, placed above the oesophagus, is analogous to the brain, although it does not exceed in size and scarcely in importance the ganglia of the lengthened eords, with which it communicates by means of a ring which embraces the oesophagus like a collar. The general covering of the body in this division is sometimes hard, sometimes soft, and is divided into segments by a certain number of transverse incisions. The muscles are always attached to the interior, and the body is usually, though not universally, provided with articulated members. It is among the classes of this form that we begin to perceive the passage from a system of circulation in closed vessels called arteries and veins, to nutrition derived from imbibition; and a corresponding passage from respiration in circumscribed organs to that performed by tracheae or air-vessels, distributed over the whole body, is likewise observable. The organs of taste and sight are the most distinct in this branch; the organ of hearing is apparent only in a single family, although we can scarcely doubt that the sense exists in others in which the organ has not been ascertained. The following classes are ranked under this great form.
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In the three preceding divisions, the organs of movement and of sensation are disposed symmetrically on both sides of an axis, with an anterior and posterior portion differing from each other. Among the zoophytes, which form the last great division, the organs are usually disposed in a radiated form. They approach the nature of plants in the extreme simplicity of their structure. They have no distinct nervous system, nor organs of the special senses; and it is barely possible to detect in a few of the species some slight vestige of the circulating system. Their respiratory organs are almost always on the surface of their bodies. The greater proportion of the classes exhibit no other intestine than a sack or caceum, and the composition of the last groups of all presents only a homogeneous pulpy mass, sensible, and endowed with motion. From a consideration of their most usual forms, the classes of this order are named Radiated Animals. They are as follows :—
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Such are the great outlines of a system which, considered in its generality, is certainly the most satisfactory which has yet appeared. Particular departments may have been filled up, modified, and perhaps improved by ingenious observers, sedulous within a limited sphere (and of these ameliorations we shall be careful to avail ourselves when we come to enter upon a detailed view of each of the classes of the animal kingdom); but the construction and position of the principal groups, their real as well as relative characters, are developed in the system of the great French anatomist, in a manner more clear and accordant with nature than in any other yet promulgated. We shall therefore in the course of this work adhere, with some slight transpositions, the reasons for which will be stated in their proper place, to the classes of Baron Cuvier. The greater extent and importance of some of these, in comparison with others, will induce us to bestow more attention and a larger space to their illustration; and as certain of the primary divisions, such as the Mollusea and Radiata, contain a greater number of classes, if not of less importance, at least by no means so strongly characterized or contradistinguished from each other as arc those of the vertebrated tribes, we shall, in presenting the history and nomenclature of such classes, group them together in such a manner as to exhibit them to the reader either under one of the great primary divisions, or as an intermediate subdivision, containing one or more classes. For example, the article Mollusea of this work will present consecutively under a single head the history and classification of the six classes contained in the second primary division so named ;—but the four classes of vertcbrated animals will be each discussed in a separate treatise. Thus mammiterous animals, birds, reptiles, and fishes, will form the articles Mammalia, Ornithology, Reptilia, and Ichthyology. The Classes of the third primary division, viz. Annelides, Crustacea, Arachnides, and Insecta, will (with the exception of the first, referred to Helminthology) likewise be treated of under distinct heads, in the alphabetical order, of the following terms Crustacea, Arachnides, and Entomology. In regard to the fourth primary division, that of the radiated animais, commonly called Zoophytes, the first class, named Echinodermata, will be treated of separately under it s ∣ own title; the second class, Entozoa, which contains the intestinal worms, will be grouped with the Annelides or red-blooded worms (as above excepted from the third primary division); and these two classes will be treated of together under the article Helminthology. The remaining classes of the Animalia Radiata, that is to say, th e Acalephae, the Polypi, and part of the Infusoria, as they form the last links of the animal kingdom, will come to be discussed with greater propriety at the concluding stage of this work, under the head of Zoophytes. Finally, that portion of the infusorial class which we have excepted in the above distribution will be found described in the present volume under the word Animalcule. This com. plctes the exposition of our zoological system.

The following enumeration exhibits à view of the terms under which the principal subjects of zoology will be explained and illustrated in the course of this work.
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Animal Magnetism. See Magnetism, Animal.