bluuebunny/crossref_metadata_2025 huggingface dataset:
Observations on Arachnactis albida, M. Sars
Authors: Bourne Gilbert C.
Published: April 2021

By the courtesy of Mr. T. A. Stephenson, of the University College of Wales, Aberystwyth, I have been entrusted with a portion of the collection of Anthozoa made by the Department of Agriculture and Technical Instruction for Ireland, in the course of marine investigations extending over a number of years. Among these were several gatherings of Arachnactis larvæ, and I have welcomed the opportunity of resuming studies which I began, but never brought to a conclusion, in 1889. At that time little was known of the anatomy and lifehistory of the Arachnactis larvæ of Cerianthus beyond what was contained in the works of M. Sars (20) and A. Agassiz (1 and 2), and finding that a species, subsequently named Arachnactis bournei by Fowler (13), was a constant element in the plankton collected at Plymouth in the summer months, I selected and preserved for microscopical study as many stages as possible, intending to publish a full account of my investigations of their structure. But hardly was the material for my projected work collected when I was asked to allow the late Prof. E. van Beneden to look at it. I accordingly sent all the specimens of Arachnactis that I possessed to the distinguished Belgian zoologist, without attaching any conditions to what I regarded as a loan of valuable material. In the absence of such conditions the loan was taken to be a gift. Prof, van Beneden made prompt use of the material that I had provided, and within a year had written the memoir (3) which has to a large extent formed the basis of his own and other subsequent work on the subject. I have no complaint to make against an esteemed and lamented friend. Prof, van Beneden gave memiore than my due share of credit in the matter, and doubtless made fuller and better use of the material than I should have done at the time. I only mention the matter now because a survey of the literature, in which my name occurs pretty frequently, suggests that I acted as a mere collector of material and threw away a good opportunity through failure to appreciate the value of what I had preserved. As it happened, a subject which I had hoped to make my own passed into other and very able hands, and the collections that I made were the prelude to the splendid memoir afterwards published by Prof. E. van Beneden (4) on the Anthozoan larvæ of the “National” Expedition. More recently large additions to our knowledge have been made by Fowler, Carlgren, McMurrich and others, and the developmental history of at least two species of Arachnactis has been so fully treated by them that little seems to be left for any subsequent investigator to deal with. But the Irish collections that have come into ray hands enable me to fill some gaps in our. knowledge of the life-history of one species—A. albida.
The Infra-cerebral Organs of Peripatus
Authors: Dakin William J.
Published: April 2021

Attached to the ventral surface of the supra-oesophageal ganglion of Peripatus and hanging therefrom are two small vesicles. They were discovered as far back as 1853 before Peripatus was regarded as an Arthropod, and Grube, their discoverer, considered them to be auditory organs (8).
Calma Glaucoides: A study in adaptation
Authors: Evans T. J.
Published: April 2021

A Detailed description of certain portions of the anatomy of a small British mollusc is here submitted, not so much as an extension of our knowledge of molluscan structure, as on account of the general biological interest of a unique metabolic type.
The Male Meiotic Phase in two Genera Of Marsupials (Macropus and Petauroides)
Authors: Agar W. E.
Published: April 2021

A very slight experience of cytological research is sufficient to impress the worker in this field with the different facilities for accurate research afforded by different organisms, and also with the importance of discovering the most favourable objects for such research. Consequently I have been making a cytological survey of such groups of Australian animals as seemed most likely to afford useful cytological material, paying at first particular attention to the Marsupials, for two reasons. The first is the well-known technical difficulties presented by the Eutherian mammals on account of the usually rather large number and tendency to clump of their chromosomes, and the second is that Jordan’s work on the American opossum (1911) showed that in this marsupial the number of chromosomes is comparatively small. Jordan determined the number as seventeen (male), but Painter (1922) has raised it to twenty-two. Up to the present we have made in this laboratory a preliminary survey of some fourteen species of Marsupials, and this paper presents an account of the more important features of two of these which have been worked out in more detail.
The Morphological Plan of the Head
Authors: Kingsbury B. F. , Adelmann H. B.
Published: April 2021

It is with some hesitation that the writers again discuss a question which has been dealt with so many times in years past. And yet their studies have led them to seriously question the correctness of the point of view which has heretofore been assumed by those who have attempted an explanation of the structural plan of the vertebrate head. It has become quite evident that a study of the developmental transformations of the head elucidates many features of head morphology which have remained obscure in spite of many attempts to interpret them. No apology is offered, therefore, for considering once again this much-worn but always fascinating theme.
On the Cranial Characters of the South African Brevicipitid, Phrynomerus bifasciatus
Authors: Villiers C. G. S. de
Published: April 2021

Much work has recently been done on the comparative anatomy and ontogeny of the shoulder-girdle of the Anura, but no attempt has been made to reinvestigate the skull with the aid of modern microtechnical methods ; it is hoped that the present paper will contribute towards the revival of interest in the osteology of the anuran cranium.
The Origin and Migration of the Primordial Germ-cells of Sphenodon punctatus
Authors: Tribe Margaret , Brambell F. W. Rogers
Published: April 2021

The primordial germ-cells of Sphenodon originate in the yolk-sac endoderm of the area opaca all round the embryo, but chiefly in a crescentic area in front of it. They differentiate first at a very early stage of development before the differentiation of the medullary plate. The primordial germ-cells are characterized by their very large size, in comparison with all the other embryonal cells, and by their content of small yolk-spherules which are sub-equal in size. The primordial germ-cells migrate through the yolk-sac endoderm and mesoderm, apparently by their own power of amoeboid movement. Many of them enter the blood-islands and the sinus terminalis. The primordial germ-cells enter the embryo either (1) passively in the venous blood-stream, or (2) actively by migration through the extra-embryonal endoderm and splanchnic mesoderm into the lateral walls and the mesentery of the midgut groove. The primordial germ-cells in the circulation reach the neighbourhood of the germinal ridges in the dorsal aorta or its branches. They then penetrate the walls of the vessels and migrate through the intervening tissues, together with those that have reached the base of the mid-gut mesentery by way of the splanchnic mesoderm and the mid-gut wall, to the germinal ridges. Many primordial germ-cells get lost during their migration. This is especially true of those travelling in the blood-stream. Such aberrant primordial germ-cells are found occasionally in almost any part of the embryo,, but occur most often in the head, especially in the region of the fore-brain. They ultimately disappear. The primordial germ-cells enter the forming germinal ridges before the coelomic epithelium covering them has begun to proliferate. The primordial germ-cells, having reached the germinal ridges, lose their characteristic yolk-content and enter on the prophase of the heterotypic division.
On the Occurrence of ‘Hepato-pancreatic’ Glands in the Indian Earthworms of the Genus Eutyphoeus Mich
Authors: Narayan Bald Harm , Behari Lal Makund
Published: April 2021

In 1883 Beddard (1) instituted the genus Typhoeus on the basis of an earthworm from Calcutta and recorded the presence of a series of about six pairs of intestinal glands lying on the dorsal surface of the gut of this earthworm which he named Typhoeus orientalis. In 1889 he (2) described another species of this genus from Darjeeling as T. gammiei, and gave a brief description of the structure of these glands in the following words: ‘The alimentary canal presents only one other feature of interest, and that is the presence of intestinal glands already recorded in T. orientalis. The glands are, however, not confined to this genus, since they exist in much greater numbers in Megascolex, and have also been described by Horst in Acanthodrilus, and by myself in Eudrilus. In Typhoeus the glands agree in their minute structure with those of Megascolex, but differ anatomically in the fact that the two glands of each pair become fused together on the middle dorsal line of the intestine, and also in the fact that the glands of consecutive segments are connected. The minute structure bears a very close resemblance to that of the calciferous glands.’1 Beddard does not describe the histology or blood-supply of the glands, but gives a diagram of a transverse section of a portion of one of the glands which is reproduced in fig. 6, Pl. 10.
Protozoa from Australian Termites
Authors: Sutherland Jean L.
Published: April 2021

Very little work has been done on the protozoa of Australian termites except for the observations of Grassi (1917), who described the faunas of Porotermes adamsoni Frogg., Coptotermes lacteus Frogg., and a species of Schedo- rhinotermes, and those of Duboscq and Grassé (1927), who worked on Calotermes iridipennis Frogg.
On Gypsina plana, and on the Systematic Position of the Stromatoporoids
Authors: Hickson Sydney J.
Published: April 2021

The study of the collection of large specimens of Gypsina plana (Carter) made by Professor J. Stanley Gardiner in the Indian Ocean, and described by Miss Lindsey in 1913 suggested to me the opinion that there is some relationship between these large Foraminifera and the ancient Stromatoporoids. My recent investigations of specimens collected by Dr. Crossland in Tahiti have so far strengthened and confirmed this opinion that I have no doubt now that the Stromatoporoids were Foraminifera. This conception of the systematic position of the Stromatoporoids is by no means new, as it was held very strongly by W. B. Carpenter and others in the nineteenth century ; but as the text-books on Palaeontology still classify these fossils with the Hydrozoa it is necessary to call for a reconsideration of the problem in the light of recent discoveries.
The Early Development of the Nephridia in Amphioxus: Part II, The Paired Nephridia
Authors: Goodrich Edwin S.
Published: April 2021

The only account we have of the early development of the paired nephridia of the pharyngeal region of Amphioxus is that given by R. Legros (1909) in a preliminary note already referred to in Part I of this contribution (p. 499 of this volume). In the same year a description was given by me (1909) of the nephridia in the larva with about ten gill-slits of the ‘primary’ or future left series ; but at this stage the paired nephridia are already well advanced. They consist of a ‘canal’ in the form of a rounded sac provided with solenocytes at its inner blind end, and an opening to the exterior at the future dorsal edge of the gill-slit. Since then I have studied in Naples the nephridia related to the developing ‘secondary’ or future right series of gill-slits in older living larvae undergoing metamorphosis, but was unable to discover their first origin. On these somewhat opaque larvae it was only possible to make out that already, when the gill was represented merely by a rounded thickening of the endodermal wall, the nephridial rudiment could be seen as a small mass of cells on its dorsal margin. By the time the gill-pouch has been formed in the middle of the thickening, and the tongue-bar has begun to grow downwards from its dorsal edge, the nephridial mass has become hollow and solenocytes have grown out from it. Soon the whole organ acquires the structure already described in the ‘primary’ series (Goodrich, 1909). The details of the development can only be worked out on sections, and it must be confessed that even in sections it is extremely difficult to make out clearly. Unfortunately I was unable to trace the early development of the nephridia belonging to the ‘primary’ series of gill-slits, since the space in which they develop is so cramped, and its walls become so closely applied to each other, that no distinct image of the origin of the nephri dial cells could be obtained. The material used consists of a large number of larvae obtained by me in Naples and a few from Heligoland, fixed and stained in various ways (see Part I, p. 500). I have to thank Prof. J. W. van Wijhe for kindly lending me some sections on which I was able to confirm some of my results.
Notes on the Development of the Germ-layers in Diprotodont Marsupials
Authors: Kerr T.
Published: April 2021

The material for this investigation was collected in Tasmania by Professor T. Thomson Flynn from animals taken in the wild during 1920 to 1929, and forms part of the marsupial and mono-treme material obtained by him by the aid of grants allowed by the Ralston Trustees and by the Grants Committee of the Royal Society. The author would like to express now his gratitude both for the opportunity of examining it and for the help and encouragement he has received during the course of the work. The material itself consists of nine series of sections of blastocysts of Bettongia cuniculus cut by Professor Flynn himself in Tasmania, and of fourteen blastocysts of Bettongia cuniculus and four of Potorous tridactylus which have been cut here. A series of early stages of these rather scarce little Marsupials is extremely hard to obtain, for only a single egg is produced at a time and it is almost impossible to breed the animals in captivity (Flynn, 1930). The blastocysts were fixed in Bouin or in Hill ‘s fluid (picro-nitric-aceto-osmic mixture), and those not cut at the time were preserved in alcohol; the whole series covers a range of development from an early unilaminar blastocyst to a fully formed primitive streak.
The Vascular System of Octochaetus thomasi
Authors: Bleakly Maurice
Published: April 2021

Posteriorly to the gizzard the dorsal vessel of O. thomasi is double, consisting of two tubes joined by a short connecting vessel anterior to the septum in each segment. There are six pairs of strongly contractile hearts in segments 8-13. The latero-intestinal hearts in segments 10-13 receive blood from the dorsal vessel and from a common trunk from the supra-intestinal and latero-oesophageal vessels, and supply blood to the ventral vessel. The lateral hearts receive blood from the dorsal vessel and supply ventro-tegumentary and ventral vessels. For complete circulation all blood must pass through the hearts. The ventral vessel, which is not contractile, receives blood from the hearts; posteriorly to the hearts the flow is backward in the ventral vessel and outward via ventro-tegumentaries and ventro-intestinals to the body and gut; anteriorly to the hearts the flow is forward, the blood leaving the ventral vessel by the commissures from which the ventro-tegumentaries of the anterior region arise. The ventral vessel is the main arterial trunk. Posteriorly to the hearts the dorsal vessel collects blood from the body and gut by dorso-tegumentaries and dorso-intestinals. The flow in the dorsal vessel, which is contractile, is forward. Blood leaves the dorsal vessel through small vessels to the latero-intestinal hearts, and larger vessels to the lateral hearts. Anteriorly to the hearts, the commissures and all vessels connected with the dorsal vessel receive blood from it. Thus, posteriorly to the hearts the dorsal vessel is venous, and anteriorly to the hearts arterial, in character. Blood from the anterior region is returned by paired latθro-oesophageal vessels to the supra-intestinal vessel and to the latero-intestinal hearts. The latero-oesophageal vessels and the supra-intestinal vessels are the main venous trunks in the anterior region.s There is no sub-neural vessel.
The Internal Anatomy of Baccalaureus with a Description of a New Species
Authors: Pyefinch K. A.
Published: April 2021

The genus Baccalaureus was formed by Broch in 1929 for Ascothoracica from the coast of Japan. He placed this new genus in the Lauridae, and described one species, B. japonicus. The internal anatomy of this species was described two years later by Yosii, and in 1934 a second species, B. maldivensis, was added to the genus.
Observations on Protozoa: I. The impermanence of the contractile vacuole in Amoeba Vespertilio.: II. Structure and mode of food ingestion of Peranema
Authors: Hyman Libbie H.
Published: April 2021

In A. vespertilio Pénard (1902) there is a continuous de novo formation of water vacuoles, each of which in turn increases to maximum size, acquires a stiffened wall, lags into the rear end of the amoeba, and discharges apparently through pressure from the gelating ectoplasm. No continuity exists between successive vacuoles. The observations indicate that the contractile vacuole system serves to discharge water necessarily taken in in hypotonic medium. The more fluid the ectoplasm and the thinner the surface membrane, the less permanent is the vacuolar system of a protozoan. In P. trichophorum Ehrb. the gullet opens and the flagellum passes inward at the anterior tip of the animal, not at the heads of the two pharyngeal rods. No evidence was found for the existence of a mouth at the rod-heads as maintained by Brown (1930), and the gullet entrance is believed to be the mouth. In feeding on large objects Peranema applies the greatly expanded gullet lips to the object and sucks in the contents; smaller objects are swallowed whole. The pharyngeal rods are not used to pierce the food object, but serve as trichites to assist the upper or more protruding lip in grasping objects and to stiffen the food-ingesting parts. Food is swallowed by peristaltic contortions.
New Species of Diatomaceæ
Authors: Kitton F.
Published: April 2021

In the previous number of this Journal, the Rev. E. O’Meara has charged me with carelessness, and thinks if I had read his papers with greater attention I should have expressed my doubts of the genuineness of his new species more cautiously. I have, therefore, read them again, in order to apologise for any misrepresentation, and correct any errors. I find two or three mistakes; viz., Cocconeis divergens should have been C. clavigera, the remarks on Navicula pellucida ought to have preceded the passage quoted by the Rev. E. O’Meara. I have also inadvertently made him the author of Raphoneis liburnica, whereas he is only responsible for the variety. With these exceptions, I really find nothing to retract. At page 91, the Rev. E. O’Meara says : “How inapplicable are some of Mr. Kitton’s observations on dredging to the forms found by me in the dredgings from Arran.” I find, on referring to his first paper, he says, “this material was procured from depths varying from ten to thirty fathoms,” &c. I do not think, therefore, I was unjustified in assuming that his material was similar to others procured from like depths, and which, in almost every case, consist of sand, animal and vegetable debris, and valves of diatoms. My copy of the ‘Microscopical Journal ‘in which his first paper appears has no description of the figures. I therefore assumed that the figures were magnified 600 diameters, as that was the degree of amplification more frequently used in the second paper. I do not find the number of diameters stated in the text. If the Rev. E. O’Meara refers to the text of his first paper, he will find Navicula pellucida is fig. 2 ; and fig. 2 in the plate is the form which, I think, resembles Navicula pandura much too elosely to entitle it to rank as a new species*. N. denticutala is fig. 3 in text. I am still unconvinced of the specific distinctness of Surirella pulchra and S. gracilis, or that they differ sufficiently from?. lata to warrant their separation from that species. I am willing to admit that a remarkable difference exists between the figures of S. pulchra and S. gracilis; viz., the crenulate margin ; alæ are also wanting, but as these differences are not noticed in the text, I am inclined to doubt the correctness of the figures, and suppose the crenulations represent the undulations of the alæ, and that the margin of the valve is not shown in the figure.
The Musculature of the Mouth-parts of Insect Larvae
Authors: Das G. M.
Published: April 2021

The principal points brought out in the foregoing discussion may be summarized as follows: The points of origin of the anterior, lateral, and posterior labral muscle identify the frons in larval insects.The hypopharynx is proximal to the insertion of the dorsal muscles (when present) of the prementum.The direction of the cardo varies with the prognathous and hypognathous conditions of the insect head.The palpifer is a secondarily demarcated portion of the stipes (Borner and Snodgrass), and cannot be a definite segment of the mouth-part limb, since no muscles take their origin from or are inserted upon it.The lacinia can be recognized by the stipital and cranial flexors, and the galea by the stipital flexor only.The cranial flexor of the lacinia is always retained and is a very important muscle in identifying the single maxillary lobe when one of the two is absent.The origin of the flexors of the lacinia and galea upon the stipes shows that the lobes belong to the stipes.The basal segment of the maxillary palp is often misinterpreted as the palpifer owing to its partial or complete fusion with the basal part of the galea, but it can be definitely identified by the insertion of the palpal muscles upon its base.The premental sclerotization may form two lateral sclerites, but it is never subdivided into a proximal and a distal sclerite.The mentum represents the united cardines of a pair of maxilla-like appendages.The submentum is a derivative of the sternum of the labial segment.The fusion of the submentum and mentum to form a single postmental sclerite is a secondary condition.The sternal muscles of the labial appendages are represented by the premental muscles having their primary origin upon the submentum, and also by the submentomental muscles.With the prognathous condition of the insect head the gula is developed from the cervical membrane.The prognathous insects having a well-developed gula are more specialized than the hypognathous insects in which the gula is either reduced or absent.The larval insects could be classified by the musculature of the mouth-parts, since each group has its characteristic musculature.
Nina: A Remarkable Gregarine
Authors: Goodrich Helen Pixell
Published: April 2021

1. The changes of shape in the protomerite sucker, together with the behaviour of the multiple caducous epimerites, have been observed in living specimens of Nina parasitizing Scolopendra subspinipes Leach in Bermuda and Malaya, and also Scolopendra cingulata Latreille from Banyuls (Mediterranean).

2. This gregarine, Nina, showed extraordinary variety of size and form in the same host specimen, but no constant differences could be discovered, in fact the gregarines appeared exactly alike morphologically from the three widely separated parts of the world. One is thus forced to the conclusion that they are all the same as Leger and Duboscq’s species from Banyuls which they call Nina gracilis Grebnicki. [This will possibly prove finally to be Kolliker’s Nina scolopendrae.]

3. Scolopendra cingulata and Scolopendra subspinipes are said to be closely related species, and we appear to have in Nina a parasite which is phylogenetically older than at least one of these hosts.

4. The elaborate method for the dispersal of the spores in water or moist places is described with an approximate time table. One striking peculiarity is the retention of the epicyte of the gamonts inside the true cyst wall. After the microgametes have entered the female side of the cyst all communication between the two sides is closed. While the zygotes are developing into spores in the female side, the male side develops into a float, gradually swelling and causing the whole cyst to rise to the surface of the water. Finally, by rupture of all its envelopes the spore mass is ejected to a considerable distance.
The Head of Xenopus laevis
Authors: Paterson Nellie F.
Published: April 2021

The foregoing account deals with some microscopic observations on the main anatomical features of the head of X. laevis, in both larval and young adult stages.

The arrangement of the lateral line sensory organs of the larva has been compared with that of the frog, and both are in general agreement with the distribution of similar organs in the Urodela.

The larval musculature is found to be similar to that of X. fraseri, described by Edgeworth. Notes regarding the changes occurring at metamorphosis are given.

The course of the head vein and internal carotid artery has been followed, as both blood-vessels are relevant to the study of the chondrocranium and nerves.

A complete study of the chondrocranium in different stages of larvae from the time of hatching up to metamorphosis reveals several points at variance with Kotthaus’s findings. Metamorphosis results in marked changes in the auditory and nasal regions. The former region has been studied by de Villiers in the adult Xenopus, and is herein only briefly reviewed. In regard to the nasal region, an account is given of the cavities and cartilages, both conforming in essentials to the typical Anuran arrangement.

The hyobranchial skeleton of the larva and young frog are in close agreement with that of mature specimens investigated by Ridewood.

The cranial nerves have been studied in some detail, and are observed to depart in some respects from those of typical Anura. The composition of the various nerves is in agreement with that of both Anura and Urodela, but the arrangement of the nerves approaches that of such Urodela as Siren (Norris), Proteus (Benedetti),and Salamandra (Francis). This is perhaps most noticeable in the innervation of the upper jaw, for a maxillary nerve is not separated from the maxillomandibular stem as in most Anura; the general cutaneous supply to the maxillary region is derived in Xenopus from the ramus ophthalmicus profundus V as in some Urodela.
The Morphology and Physiology of the Salivary Glands of Hemiptera-Heteroptera
Authors: Baptist B. A.
Published: April 2021

The salivary glands of the Heteroptera consist of a pair of primarily bilobed principal glands and accessory glands which vary very greatly in form and structure in different families.

The glands are usually supplied with tracheae, and the principal glands are invested by a nervous plexus which is supplied by a glandular nerve from the hypocerebral ganglion of the stomatogastric system.

The principal salivary gland of Notoneeta is characterized by the presence of large cells having zymogen granules and by the storage of fluid secretion in vacuoles. In contrast, most of the remaining Heteropteran salivary glands belong to the vesicular type, having a one-layered glandular epithelium made up of small cells which discharge their secretion into a large central storage cavity or axial canal. This type of gland lacks zymogen granules but has small dense masses of reserve material in the basal or outer parts of the cells. There is normally no difference in the structure of the glandular epithelium in the different lobes. The accessory glands are either in the form of a thin-walled bladder-like vesicle, or are tubular or duct-like ; they seem to be purely a development of the primary conducting glandular system, and are thus homologous with the salivary reservoir of other orders. All the information obtained in this work is strongly against the idea that the various lobes of Hemipterous salivary glands produce widely different chemical substances, each with a special function. The results obtained by Fauré-Fremiet have not been confirmed.

Except with blood-sucking forms digestive enzymes were always found in the glands, two enzymes being the maximum number found in any particular gland. The enzymes were found to be always related to the type of food consumed, and were those concerned with the digestion of that particular component of the food which was present in the greatest proportion. In no case was a cellulase found. An anti-coagulant principle was found to be present in the glands of blood-sucking forms.

The accessory glands appear to produce only a watery secretion, enzymes being absent.

The pH of the principal gland is generally slightly acid, while that of the accessory gland is neutral.

Mitochondria and Golgi bodies typical of insect tissue are present in certain glands, but show no relation to the secretion granules, and thus do not appear to contribute to secretion synthesis.

From a number of experiments it appears that the action of the digestive enzymes is not sufficiently rapid for external digestion to take place to any great extent. It seems, however, certain that quite an appreciable quantity of the injected saliva is imbibed again, and that the salivary digestion continues in the stomach, where the food taken in is first stored. The pH activity range of the enzymes is in general wide.
The Tegumental Glands in the Land Isopoda A. The Rosette Glands
Authors: Gorvett H.
Published: April 2021

The land Isopoda possess five (or possibly six) distinct varieties of tegumental gland, and these are briefly described. Of these, only the rosette glands are known to occur outside the group. The rosette glands of the Isopoda are similar to those of the Decapoda, but are confined to the head and mouth-parts. The structure and development of the rosette glands in Porcellio scaber Latr. are described. Activity is intimately connected with the moulting cycle, the glands reaching maturity and liberating their secretion only during the few days before ecdysis. The contents of the glands and their ducts show the same staining reactions as the cuticle. The cuticle first appears after the formation of new chitin has begun and increases in thickness with it. The thickness of the cuticle is greatest in the mouth-parts, where the ducts of the rosette glands open. The function of the rosette glands in the Isopoda is similar to that of the corresponding glands in the Decapoda, namely to secrete the layer of cuticle on the surface of the integument. Seven other species of Isopoda, from a wide range of habitat, were examined. Rosette glands similar in structure and distribution to those of Porcellio, and presumably having the same function, were found in every case.
The Histochemical Recognition, of Lipine
Authors: Baker John R.
Published: April 2021

The purpose of the investigation described in this paper was to find a rigorous and sensitive histochemical colour-test for the demonstration of lipine in plant and animal tissues. Full details are given of two new tests, called the acidhaematein and the pyridine-extraction tests. The presence of lipine is reliably indicated by the use of the two tests in conjunction. The acid-haematein test is derived from that of Smith and Dietrich, but unlike the latter gives a positive reaction with pure lecithin. It is also much more sensitive. Diverse organic compounds that occur in the tissues of plants and animals were deposited on paper and subjected to the acid-haematein test. The test was shown to be negative to members of all the groups of such substances that were studied, except lipines and certain proteins. The pyridine-extraction test serves to separate the positive reaction with lipines from that with certain proteins. Its validity was proved by experiments on known substances deposited on paper. In the pyridine-extraction test, tissues are extracted with hot pyridine before subjection to the aeid-hamnatein test. The tendency for certain proteins to give a positive reaction is now somewhat increased, while lipines are wholly negative. Any organic substance that reacts positively to the acidhaematein test but negatively after pyridine extraction consists of or contains lipine. Mitochondria are among the tissue-constituents that are shown by the tests to contain lipine. It has long been regarded as probable that they do so ; but they respond negatively to the Smith-Dietrich test, and there has not previously been rigorous proof by any in situ histochemical method that they do in fact contain lipine.
Note on a Point in the Habits of the Diatomaceæ and Desmidiaceæ
Authors: Edwards Arthur Mead
Published: April 2021

Although most writers on the subject are in the habit of stating that many of the genera of Diatomaceæ in the living state are free, or non-adherent to other larger algæ or submerged substances, yet always since I first began the study of the Protophytes, as is well known to my fellow-students with whom I have from time to time discussed the subject, I have held that all species are, at some period of their existence, in an adherent or attached condition, growing upon, for the most part, aquatic vegetation of a larger size. I have also frequently expressed the opinion that the adherent condition of any species was but temporary and conditional ; otherwise I could not see how the wide distribution of forms, such as Cocconeis scutellum, an extremely widely diffused marine species usually found attached to larger algæ, or Tabellaria fiocculosa, an equally cosmopolitan fresh-water species found almost invariably attached, was provided for, as no motile spores of any kind are known to exist in this family, although such may be the case.
Immersion Objectives and Test-Objects
Authors: Mayall John
Published: April 2021

The presentation of Dr. Woodward’s photographs1 of Robert’s Nineteen-band Test-plate, brought to the notice of the Society by the Hon. Secretary, Mr. Jabez Hogg, affords au opportunity of making a few remarks on their value as a record of what has been done in America in resolving these marvellously fine lines ; and as in my experiments 1 found some difference in the results obtained on Nobert’s plate by the immersion and the dry objectives, I think it will interest the Society to be informed of these results, because the relative separating and defining power of the two systems has not received that attention which I and many others think it deserves.
The Prothoracic Glands of some Coleopteran Larvae
Authors: Srivastava U. S.
Published: April 2021

The paired prothoracic glands of the larvae of 15 species of Coleoptera have been described. Each is a syncytial or cellular band attached at its ends to the dorsal and ventral tracheal trunks running from the prothoracic spiracles to the head, or the branches of these trunks; the gland may be spread over one or both of the tracheal trunks to a varying degree, shows no nuclear divisions during postembryonic development, and has no nerve-supply. There seems to be a tendency for the glands to be more anteriorly placed in the primitive groups and more posteriorly placed in the specialized ones. No relationship seems to exist between the morphological and histological nature of the gland and the taxonomic position of the insect, nor is there any proportionality between the size of the gland or its nuclei and the size of the insect. But there seems to be a direct relation between the volume of the whole gland and its total nuclear volume, and an inverse relation between the number of nuclei in the gland and the size of the individual nuclei.
The Histology of the Tube-feet and Clavulae of Echinocardium cordatum
Authors: Nichols David
Published: April 2021

The histology of the oral feeding, dorsal funnel-building, sub-anal, sensory, and respiratory tube-feet and the clavulae of the fascicles of Echinocardium cordatum is described. The penicillate tube-feet, all superficially similar, are shown to possess histological differences which reflect their function: the burrow-building tube-feet (dorsal and sub-anal), which plaster mucus on to the burrow walls, possess mucus glands surrounded by a basket work of muscle-fibres for more efficient discharge, whereas the feeding tube-feet, needing a sticky disc, have glands lacking such fibres. The sensory tube-feet lack definite discs but possess greatly enlarged subepidermal nerve plexuses. The respiratory tube-feet have a thin, much-folded wall; no nervous tissue was detected and no muscle-fibres. Each clavula has two longitudinal bands of cilia, opposite each other, on the stem and a distal knob in which mucus glands are embedded.
An Improved and Rapid Embedding Method
Authors: Chayen J. , Gahan P. B.
Published: April 2021

Plant tissues may be embedded in half the time taken for paraffin embedding if acetone is used as the dehydrating and infiltrating agent, and the tissue is embedded in ester wax. This procedure retains appreciably more lipid material inside the cells than does the more usual technique, even when the tissue has been fixed in osmium tetroxide or in La Cour’s 2BE.
What is the ‘Golgi Apparatus’ in its Classical Site within the Neurones of Vertebrates ?
Authors: Malhotra S. K.
Published: April 2021

A reticulum can be seen by interference microscopy in the cytoplasm of the living neurone of vertebrates. The reticulum consists of irregular, massive bodies and thin strands. There are also well-defined spaces in the cytoplasm, in contact with the reticulum; they are usually crescentic.

The massive bodies are the objects commonly called Nissl bodies. The thin strands are the basiphil threads clearly recognized by Nissl himself as constituting a part of his basiphil material.

The classical ‘Golgi apparatus’ of the cell-body of the neurone of vertebrates consists of a deposit of silver or of osmium on the cytoplasmic inclusions mentioned in the first paragraph, but especially on the basiphil strands, which have a particular affinity for silver.

At the base of the axon there are non-basiphil threads, which are also blackened by the Golgi methods.
Neurosecretion in the Brain of the Larva of the Sheep Blowfly, Lucilia caesar
Authors: Fraser Alastair
Published: April 2021

Six groups of neurosecretory cells were identified in the brain of the mature larva of Lucilia caesar. Five of these groups belonged to the category of medial neurosecretory cells and one to that of lateral neurosecretory cells. The groups differ in position, cell size, staining characteristics, and sequence of activity. It is apparent that only some of the groups are concerned with the process of thoracic gland activation, though all function during metamorphosis. At least one group, not concerned in thoracic gland activation in the non-diapause larva, is continually active during diapause.
The Use of Teased Preparations and Frozen Sections in Quantitative Studies of Mammalian Peripheral Nerve
Authors: Wendell-Smith C. P. , Williams P. L.
Published: April 2021

When teased preparations of peripheral nerve are examined, the highly refractile myelin sheath acts as a convex lens and affects estimates of axon diameter and sheath thickness. The construction of ray diagrams for different axon-sheath ratios indicates that the degree of magnification varies with this ratio. Models and experiments in which teased fibres were immersed in fluids of different refractive index show that magnification also varies with the relative refractive indices of the sheath and the immersion medium. Fibres from the nervus gastrocnemius medialis (NGM) of the rabbit were teased in Ringer’s solution and measurements made with a polarizing microscope. A regression line for 2 × apparent sheath thickness on external diameter was calculated.

Frozen sections (Williams, 1959) of the NGM were prepared, and from these individual fibres were tipped over on to their sides by micromanipulation. A magnification effect similar to that existing in teased fibres was thus introduced and a comparison of their apparent axon diameters was made valid. An analysis of co-variance showed no significant difference in variance, slope, or elevation. It was concluded that these frozen sections provided a satisfactory basis for an estimate of magnification, and that estimates of size relationships made on these frozen sections reflected the natural state as closely as estimates made on isolated teased fibres and corrected for magnification.

A regression line was derived for 2 × myelin sheath thickness on external diameter from intact frozen sections. This line was compared with the regression line for teased fibres and percentage magnification of the axon plotted against external diameter. The graph indicated that this percentage magnification decreased with fibre diameter from over 40% to under 20%.
A Note on Berenbaum’s Acetone / Sudan Black Technique for Bound Lipids applied to Insect Cuticle
Authors: Locke M.
Published: April 2021

Colouring by Sudan black in acetone at 37° to 60° C is not a histochemical test for bound lipids.
An Account of Larval Budding in the Compound Ascidian, Hypsistozoa fasmeriana
Authors: Brewin Beryl I.
Published: April 2021

Larval budding in Hypsistozoa fasmeriana is in many ways unique in the subfamily Holozoinae. The stolon, which projects from the left side of the oozooid, is large (235 μ in diameter, 1 · 8 mm in length) and reaches maximal size before severance of buds occurs. The buds arise one at a time and 9 to 14 are formed.

Test forms rapidly between a newly severed bud and the remainder of the stolon. Thus the buds are moved along an arc of a spiral which runs from the left side of the oozooid somewhat anteriorly across the ventral side and posteriorly up the right side. By the end of bud formation the first-formed bud occupies the most posterior position, lying high up on the right side of the oozooid.

Each larval bud develops directly into a blastozooid and by the time the tadpole becomes free-swimming there is a considerable degree of organogenesis. The blasto-zooids together with the oozooid form a ring of zooids tilted slightly away from the vertical. After metamorphosis of the tadpole this ring becomes horizontal, but the tilt is still maintained with the oozooid occupying the most elevated position. Thus in the young colonies the plane of the head is slightly off the horizontal—an arrangement which persists throughout the life of the colony.

The development of larval buds in this ascidian is not delayed until after dedifferentiation of the oozooid, as is the case in the other Holozoinae. The blastozooids function simultaneously with the oozooid. They do not, however, become sexually mature, being presumably of sub-maximal size for the species.

The newly severed bud differs from that of other Holozoinae in having an extensive epicardial tube and a thick mesenchymal layer of densely granulated cells. The epicardium of the blastozooid is formed from the posterior end of the original epicardial tube. It remains single. The neural tube arises from the left peribranchial sac.

H. fasmeriana forms a close link between the sub-family Holozoinae and the subfamily Polyclininae. It resembles the Holozoinae in form of gut, position and mode of origin of the brood pouch, and position of the cardio-pericardium. It shares with the Polyclininae the post-abdominal position of the gonads as well as the structure and organogenesis of the buds.
Is Protoplasm ever Fluid?
Authors: Wilson Walter L. , Heilbrunn L. V.
Published: April 2021

From the very beginning of the study of protoplasm, biologists have been concerned with the question whether protoplasm commonly was fluid or whether it has some of the properties of a solid. With the rise of the science of colloid chemistry, this question became translated into terms of sol and gel.
The Initial Cooling of Tissues in the Freezing-drying Technique
Authors: Zlotnik I.
Published: April 2021

When a mixture of dry ice and pentane is subjected to high vacuum for one hour the temperature of the mixture is reduced to − 125 ° C.

The low temperature of the dry ice/pentane mixture persists for about h and rises only very slowly thereafter.

The chilled dry ice mixture when used for the initial cooling of tissues produces good cytological preservation.
The Cuticle and Wax Secretion in Calpodes ethlius (Lepidoptera, Hesperidae)
Authors: Locke M.
Published: April 2021

Larvae of Calpodes ethlius have an area of integument specialized for the secretion of long hollow filaments of wax. The epicuticle in this region has numerous cratershaped tubercles about 0·5μ in diameter, from the rims of which the filaments are secreted. Rows of tubes 60 A in diameter emerge round the rim of each crater. The wax is supposed to traverse these tubes and they have been termed ‘wax canals’. On the inside the wax canals ramify irregularly. Tubes that appear to be similar occur elsewhere in the epicuticle, where they may be concerned with normal wax secretion. The epicuticle consists of cement, a cuticulin layer 60 to 100 A thick, and an inner dense layer of variable thickness. Microfibres are described in the endocuticle.
A Contribution to the Life-history of the Brachiopod Tegulorhynchia nigricans
Authors: Percival E.
Published: April 2021

This study of the development of a rhynchonellid brachiopod has revealed marked differences from that of Terebratella inconspicua (Percival, 1944). These principally concern the origin of the mesoderm and of the lophophore. The origin of the right and left mesoblastic sacs in Tegulorhynchia and in Terebratella depends on the stage at which the blastoporal groove exerts its influence, earlier in the former, leading directly to their formation, later in the latter, leading indirectly to their formation. The subsequent division into anterior and posterior sacs is similar in both genera. The lophophore of Tegulorhynchia is the product of the anterior lobe, and considerable centripetal movement occurs during the sinking of the centre from which the brachial fold (or buccal lip) is derived. The process of formation of the lophophore in Terebratella can be regarded as a much shortened version of that which occurs in Tegulorhynchia. In the latter genus the origin of the brachial fold is elaborate and protracted, while in the former the brachial fold does not appear until 8 pairs of cirri have been formed.
Histochemical Observations on the Succinic Dehydrogenase and Cytochrome Oxidase Activity in Pigeon Breast-muscle
Authors: George J. C. , Talesara C. L.
Published: April 2021

Histochemical and cytochemical observations were made on the exact localization and distribution pattern of succinic dehydrogenase system and cytochrome oxidase in the pigeon breast-muscle by employing slightly modified methods. Succinic dehydrogenase activity, which was not detected earlier either histochemically or biochemically in the broad white fibres, was demonstrated by using a modified incubation medium under strictly anaerobic conditions, with neotetrazolium as the hydrogen acceptor. The size, localization, and distribution pattern of the histochemically demonstrable diformazan and indophenol blue granules showed a more or less close resemblance to the mitochondrial staining in the individual red as well as white fibres. The occurrence of high oxidative metabolism in the narrow red fibres was revealed by the presence of a large number of succinoxidase-positive granules in these fibres. On the other hand, the presence of fewer, smaller granules indicated very low oxidative metabolism in the broad white fibres.

The presence of the fewer, smaller succinoxidase-positive granules in the broad white fibres nevertheless shows that these fibres too possess mitochondria where at least a certain amount of oxidative activity does take place, and that they are to be considered as analogous to the white fibres of the other vertebrate skeletal muscles. It is also suggested that these granules are to be considered as mitochondria in the general sense and that the distinction between sarcosomes and mitochondria as proposed by previous authors needs reconsideration.