bluuebunny/crossref_metadata_2025_split huggingface dataset:
On the Inadequacy of the Cellular Theory of Development, and on the Early Development of Nerves, particularly of the Third Nerve and of the Sympathetic in Elasmobranchii
Authors: Sedgwick Adam 
Published: April 2021

ABSTRACT
It is now more than ten years ago since I first pointed out the inadequacy of the cellular theory of development. That I did so in a very guarded manner need hardly be said; but now, after ten years of mature work, I feel justified in giving a stronger expression to the views which I then formed, and which all my subsequent work has amply confirmed. My words then (in 1883) were as follows :—” In short, if these facts are generally applicable, embryonic development can no longer be looked upon as being essentially the formation by fission of a number of units from a single primitive unit, and the co-ordination and modification of these units into a harmonious whole. But it must rather be regarded as a multiplication of nuclei and a specialisation of tracts and vacuoles in a continuous mass of vacuolated protoplasm.” Again, in 1888, in the preface to my “Monograph on the Development of the Cape Species of Peripatus,” 1 I wrote: “It would appear, indeed, that in Peripatus the cells of the adult, in so far as they are distinct and sharply marked off structures, are not, as appears to be generally the case, present in the earliest embryonic stages, but are gradually evolved as development proceeds. In other words, the cell-theory, if it implies that the adult cells are derived from embryonic cells which have been directly produced by the division of the ovicell, does not apply to the embryos of Peripatus.”
On the Growth in Length of the Frog Embryo.
Authors: Assheton Richard 
Published: April 2021

ABSTRACT
In some previous papers on the development of the rabbit I have attempted to show that there are two main centres of growth, each in itself tending to produce a radially symmetrical form; but since these two centres of growth are situated eccentrically to each other the resulting embryo is cylindrical, and subsequently bilaterally symmetrical.
On the Structure of Vermiculus pilosus
Authors: Goodrich E. S. 
Published: April 2021

ABSTRACT
In 1892 (3a) I published a short description of an interesting new Oligochæte I had found on the sea-shore near Weymouth. Since then I have obtained more material, which I have worked at in Professor Lankester’s laboratory at Oxford, and am now able to give a more complete and accurate account of its anatomy.
Sedgwick’s Theory of the Embryonic Phase of Ontogeny as an aid to Phylogenetic Theory
Authors: MacBride E. W. 
Published: April 2021

ABSTRACT
In a recent number1 of this Journal there appeared a paper by Mr. Adam Sedgwick on the significance of the embryonic phase in development, which embodies a principle which, if true, seems to me well fitted to throw light on some obscure problems in morphology.
On the Variation of Haliclystus octoradiatus
Authors: Browne Edward T. 
Published: April 2021

ABSTRACT
A normal specimen of Haliclystus octoradiatus, Clark, has eight adradial groups of tentacles; eight adradial genital bands; eight colleto-cystophors, one midway between every two groups of tentacles; and four internal, interradial septa.
The Collar-cells of Heterocœla
Authors: Bidder George 
Published: April 2021

ABSTRACT
The collar-cells are in normal life short and barrel-shaped, with separated cylindrical collars, which are never united. In certain pathological conditions, probably connected with suffocation, they elongate very greatly, diminishing in the diameter of their upper part, or “collum;” and in some species, though not in Sycon compressum, the collars may then come into contact. In certain other pathological conditions the collar is lost, though apparently it can be regenerated. These metamorphoses appear unconnected with the ingestion of food, which also was not found to induce any migration of the collar-cells. On the other hand, migration seemed to occur under exceptionally unhealthy conditions.
The collar is made up of (in Sycon compressum) about thirty parallel rods united by a film of some other substance. The flagellum is intimately connected with the nuclear membrane. There is an interstitial substance between the bodies of the cells. The area inside the collar appears to be provided with a sphincter membrane.
Cells preserved and cut by the paraffin method show an average contraction of 5:4 linear in the best sections. In most preparations this contraction is uneven, producing Sollas’s membrane and other fictitious appearances.
Further Remarks on the Cell-theory, with a Reply to Mr. Bourne
Authors: Sedgwick Adam 
Published: April 2021

ABSTRACT
In a paper published last autumn (this Journal, vol. 37), I called attention to the apparent inadequacy of the celltheory. Recently a criticism upon my article has appeared from the pen of Mr. G. C. Bourne, to which I may be allowed to devote a few words. But before replying to Mr. Bourne, I should like to state my position with regard to the theory a little more fully than I have hitherto done. In my previous communication I used theword “inadequacy” because it seemed to me to express, as nearly as possible, my own views with regard to the theory. A theory to be of any value must explain the whole body of facts with which it deals. If it falls short of this, it must be held to be insufficient or inadequate ; and when at the same time it is so masterful as to compel men to look at nature through its eyes, and to twist stubborn and uncomformable facts into accord with its dogmas, then it becomes an instrument of mischief, and deserves condemnation, if only of the mild kind implied by the term inadequate.
The Early Development of Amia
Authors: Dean Bashford 
Published: April 2021

ABSTRACT
Ganoids, or more accurately Crossopterygians and Chondrostean Actinopterygians, must be looked upon as, in many ways, a transitional and intermediate group. For, on the one hand, the evidence is becoming conclusive that the Teleosts are to be regarded as its highly differentiated descendants; and, on the other hand, its most primitive members have certainly the closest ties of kinship with both the early sharks and lungfishes.1
The Constitution and Development of the Society Of Termites: Observations On their Habits; With Appendices on the Parasitic Protozoa Of Termitidæ, and on The Embiidæ
Authors: Grassi B. , Sandias A. 
Published: April 2021

ABSTRACT
The memoir, of which I have made the following translation, was originally published in the ‘Atti dell’ Accademia Gioenia di Scienze Naturali in Catania,’ ser. 4, vols, vi and vii (1893–4), but has become more generally known through the appearance of a separate edition in the former year. But though its value was immediately recognised, the work has not yet become familiar to an extent commensurate with the importance of its contributions to natural science.
An Endeavour to identify Palmoglcea Macrococca (Kütz.) with Description of the Plant believed to be meant, and of a New Species, both, however, referable rather to the Genus Meostænium (Näg.)
Authors: Archer William 
Published: April 2021

ABSTRACT
Before proceeding to the subject proper of this communication I shall call to mind the characters of the genus Palmoglcea (Kütz.) itself, thus defined by Kützing: *— “Stratum gelatinosum difforme indeterminatum, ex cellulis sparsis polygonimicis in substantia gelinea nidulantibus, compositum.” Now, such a diagnosis of the genus, while it does not seem calculated to exclude all that it ought, appears to me to omit an additional important character pervading all the species intended to be included therein (if we except, as we ought, Palmoglœa Roemeriana Kütz.), and that is the elongate or oblong form of the cells. As I should be disposed to understand it, putting aside his Palmoglœa Roemeriana, Kützing must have established his genus Palmoglœa for the reception of, and meant it to include, all those Palmellaceous Algæ (except the one species forming his genus Trichodictyon, separated from his Palmoglœa with little reason) possessing oblong, cylindrical, or elliptic cells, with granular contents, each cell possessing only a single simple, special, mucous coat not persistently included coat within coat, the whole becoming confluent into an indeterminate gelatinous stratum of greater or less density or tenuity. It is true that, of course, in the specific characters and diagnosis of subgroups, the elongate form of the cells is alluded to, but I do not think a character so obviously generic should have been left to be sought for amongst the specific. But the fact of Roemeriana being included in the genus compelled him to omit this character from the diagnosis.
On Hetoroplana, a New Genus of Planarians
Authors: Willey Arthur 
Published: April 2021

ABSTRACT
Since I have been in Lifu I have obtained one specimen only of a very remarkable flat-worm which must form the type of a new genus and a new family. The quite unexpected relations of symmetry presented by this form, which I will call Heteroplana, speak for the accuracy of the observations, although I should be more satisfied if I could obtain more examples of it.
On the Relation of the Arthropod Head to the Annelid Prostomium
Authors: Goodrich Edwin S. 
Published: April 2021

ABSTRACT
The question of the segmentation of the Arthropod head, and of the homology of the preoral region in Arthropods and Annelids, has for long excited the interest of naturalists, giving rise to much discussion, and leading investigators to the discovery of many important facts. The present paper, written at the suggestion of Professor E. Ray Lankester, does not claim to be a contribution to our knowledge of the problems involved, nor an exhaustive history of the subject; it aims neither at originality nor completeness, but is merely an attempt to give a plain account of the questions at issue, and the advance that has been made towards answering them, for the benefit of those who have not devoted special attention to the subject.
On the Development of the Californian Hag-fish, Bdellostoma Stouti, Lockington
Authors: Dean Bashford 
Published: April 2021

ABSTRACT
Dr. Howard Ayers, in a lecture before the Wood’s Holl Biological Laboratory,1 has given a detailed account of the occurrence of the Pacific Hag-fish, Bdellostoma Dombeyi (= Stouti), in the Bay of Monterey. Its great abundance in this region gave promise of material for the study of the development of a Myxinoid ; or, at all events, the chances to obtain these valuable stages seemed far more favorable here than in the European localities, mainly in the North Sea, where the eggs of Myxine had long been sought. Among the zoologists who endeavoured to secure hag-fish embryos in California Professor G. C. Price, of the Leland Stanford, Junior, University, was the first to succeed, and he has already published two accounts of his studies.2 During the past summer additional developmental stages, including a number of the earlier ones, were collected by the present writer during a visit (July, August, September) at the Hopkins Marine Laboratory.
Note on a New British Echiuroid Gephyrean, with Remarks on the Genera Thalassema and Hamingia
Authors: Herdman W. A. 
Published: April 2021

ABSTRACT
On the dredging expeditions of the Liverpool Marine Biology Committee we endeavour as much as possible to try new methods of collecting, or to modify old methods, with the object of securing animals whose special habitat renders them difficult of capture. With this end in view, when dredging last Easter (April, 1896) in the deep depression that runs down between the Isle of Man and Ireland, it occurred to me to try a haul of the large fish-trawl (50-foot beam) which we had on board, but to steam very much more slowly than is customary when trawling, so as to allow the foot-rope to dig deeply into the stiff blue mud which I knew we were on. We went dead slow with plenty of the heavy steel warp out, the result being—as the event proved—that a good deal of the warp lay on the bottom, and so made the pull on the trawl practically a horizontal one. As a consequence of this we must have sliced off the top six inches to a foot, possibly, of the bottom deposit as we went along. When the trawl came up it was half full of the blue mud, and we found it impossible to get the net on board. After steaming round for a little a good deal of the mud was washed out through the meshes, and the cod-end was then hoisted on board by means of the tackle, and ripped up so as to precipitate upon the deck a seething mass of mud, spawning fish,1 and Invertebrates, which spread over a considerable area to a depth of about a foot.
On Drepanidotænia hemignathi, a New Species of Tapeworm
Authors: Shipley Arthur E. 
Published: April 2021

ABSTRACT
The specimens of the above-named tapeworm, of which I received but ten, are all small; they vary in length from 10 mm. to 22 mm. The head is very small; immediately behind it, there being practically no neck, the body begins to broaden out, and in some specimens the proglottides attain a width of 2 mm. The segmentation of the body commences immediately behind the head, and is very well marked a little further back. The posterior border of each segment overlaps the succeeding one with a prominent edge or rim ; this is well shown in longitudinal section (fig. 6). The number of segments varies from some fifty to sixty to over a hundred. The measurements given above are about the average, but, as is well known, tapeworms are extremely extensible animals, and this to a great extent diminishes the value of figures quoted in reference to their size. In some specimens the body is stretched, and the length of the segments equals one half or even two thirds of their breadth, but in the commoner forms the segments are very short and broad, sometimes eight or ten times as broad as long. They are flattened, as is seen in transverse section, and sometimes, especially towards the posterior end, the whole body is hollowed so that each segment is curved. The most posterior segments, which are crowded with embryos well advanced in their development, are rounder, less flattened, longer, and they readily broke off.
Studies in Dedifferentiation. 5. Dedifferentiation and Reduction in Aurelia
Authors: de Beer G. R. , Huxley J. S. 
Published: April 2021

ABSTRACT
Professor Garstang called the attention of one of us (J.S.H.) to the fact that the medusa Aurelia, when left without food, underwent a remarkable decrease in size accompanied by interesting form-changes. Accordingly, a number of medusae of Aurelia aurita were obtained from Plymouth, and placed in breffits containing sea-water under aeration, in the Department of Zoology and Comparative Anatomy, Oxford.
On Proterythropsis vigilans, n.sp
Authors: Marshall Sheina M. 
Published: April 2021

ABSTRACT
The genus Proterythropsis was founded by Kofoid and Swezy (1) to contain a Gymnodinian found by them at La Jolla, California, in the month of July. It possessed a pigment spot and lens, and was characterized by a stout posterior tentacle. Only one specimen was obtained and it was named P. crassicaudata. In this paper I describe a new species which differs from P. crassicaudata in several respects and to which I give the name P. vigilans. It is shown from the dorsal side in the coloured figure on Pl. 9, and from the ventral side in Text-fig. 1.
On the Reproductive Processes of the Earthworm, Lumbricus terrestris
Authors: Grove A. J. 
Published: April 2021

ABSTRACTDuring the sexual congress of L. terrestris, the co-operating worms become attached to one another in a head-to-tail position in such a way that segments 9-11 of one are opposed to the clitellum of the other, and vice versa. At these points the attachment between the worms is an intimate one, assisted by the secretion of the glands associated with the diverticula of the setal pores found in certain segments, and is reinforced by the mutual penetration of the setae into the opposed bodysurfaces. There is also a slighter attachment between segment 26 of one and 15 of the other. Each worm is enclosed in a slime-tube composed of mucus secreted from the epidermis. The exchange of seminal fluid is a mutual one. The fluid issues from the apertures of the vasa deferentia in segment 15, and is conducted beneath the slime-tube in pit-like depressions in the seminal grooves, which extend from segment 15 to the clitellum on each side of the body, to the clitellum, where it accumulates in the space between the lateral surfaces of segments 9-11 of one worm and the clitellum of the other. Eventually it becomes aggregated into masses in the groove between segments 9 and 10, and 10 and 11, and passes thence into the spermathecae. The seminal groove and its pit-like depressions are brought into existence by special muscles lying in the lateral blocks of longitudinal muscles of the body-wall.
Rhynchodemus britannicus, n.sp. A new British terrestrial triclad, with a note on the excretion of Calcium Carbonate
Authors: Percival E. 
Published: April 2021

ABSTRACT
The terrestrial triclad fauna of the British Isles is very scanty. Up to the discovery of B. Scharf fi, von Graff (3), in Dublin the only indigenous species known was R. t e r r estr is, which occurs commonly in England and Ireland (von Graff, 3). Recently Professor A. Dendy (2) reported the discovery of R. Scharffi at Chiswick, and by his great kindness I was able to examine one of the specimens found there (see below). Dr. Orton of the Marine Biological Laboratory, Plymouth, informed me that he had recently found, in a garden at Plymouth, several terrestrial triclads, one of which he had sent to Professor Dendy. This specimen, which was described as being black when alive, was, in the preserved condition, greyish brown to chocolate-brown dorsally, and pale grey along the creeping sole. Unfortunately it was immature, and could not be defined specifically, but was obviously a Rhynchodemus. The length was 2·4 cm. and breadth 1 ·5 mm. in the preserved state. Dr. Orton also spoke of a fawn-grey specimen, more than two inches long, which unfortunately deliquesced. I have no doubt that this was a representative of the new species. Mr. J. T. Wadsworth, of Manchester University, sent me two specimens of sulphur-yellow colour found in a garden at Stockport. These answered very closely to the description of the external features of R. Scharffi, but on further examination were found to belong to the new species.
Cytological Observations on Gymnostomatous Ciliates, with a Description of the Maturation Phenomena in Diploid and Tetraploid Forms of Chilodon uncinatus
Authors: MacDougall Mary Stuart 
Published: April 2021

ABSTRACT
Some form of supporting structure is found around the oral opening in many species of ciliates. This varies from a few trichites around the mouth, as in Spathidium spathula, or a simple tube of trichites, as in Prorodonteres, to the very complicated apparatus found in various species of Chilodon and Nassu1a. The early investigators designated this structure the pharyngeal basket or ‘Reusenapparat ‘. There are many references to this organelle, either of a descriptive or speculative nature, particularly as to its function. Kent (1881) gives a partial account of its behaviour in division and encystment, and there is an incomplete account by Enriques (1908) of its behaviour in division and conjugation. It seems desirable, therefore, to make an extended study of the structure in order to determine its origin, if possible, and its behaviour in the complete life-cycle. This naturally led to a study of the basket during division, conjugation, and encystment phases, and the material obtained for this purpose was found to be favourable for the further study of nuclei during division and conjugation.
Peristalsis in the Malpighian tubules of Diptera, Preliminary account: with a note on the elimination of Calcium Carbonate from the Malpighian tubules of Drosophila funebris
Authors: Eastham L. 
Published: April 2021

ABSTRACT
The proximal regions of the Malpighian tubules of Drosophila funebris and Calliphora erythrocephala are supplied with systems of circular and longitu-dinal muscles external to the basement membrane. These muscles are continuous with those of the mid-gut. There is a terminal muscle to each anterior tubule in Drosophila funebris connected to the alar muscles of the pericardial septum. Peristalsis has been observed in the proximal regions of the tubules, caused by the circular muscles. The tubules exhibit a waving movement, probably due to the longitudinal muscle-bands of the lower or proximal ends of the tubules. Calcium carbonate is stored in the terminal portions of the anterior tubules of Drosophila funebris. This calcium carbonate is not eliminated at the beginning of metamorphosis, but is passed to the gut about the sixth day of pupal life, and is only expelled from the body on the emergence of the adult. Calcium carbonate is found in the Malpighian tubules of the adult Drosophila funebris.
Notes on the Choanoflagellate, Codosiga botrytis, Ehrbg
Authors: Lapage Geoffrey 
Published: April 2021

ABSTRACT
This paper records observations upon living specimens only of the Choanoflagellate Codosiga botrytis, Ehrbg. The study of the organism does not support the view put forward by Entz, Franze, and Ehrlich, that the collar is a spiral membrane. It shows that the collar of Codosiga botrytis is, as earlier workers correctly stated, a protoplasmic, flexible, retractile, conical membrane, closed on all sides except on its upper, free surface. Its function as an apparatus for catching food is discussed. The flagellum and the currents it produces are described, and the part played by them in bringing food to the collar, and their other functions, are explained. It is shown that the food, when it has been caught by the collar, passes down the outside of that structure to be ingested at or below the middle of the body and not at its upper end and never by the area enclosed by the collar. Defoe-cation, however, invariably occurs from the area enclosed by the collar. The actual ingestion of food is effected by means of a rhythmical contraction which passes round the upper end of the body just below the collar, acting in conjunction with the mucous envelope in which the body is enclosed. As this wave of contraction passes round it creates a space between the body and the envelope at successive points along its course. It is this space which, being seen only in profile at the sides of the body, has been interpreted either as a travelling vacuole (Bfitschli) or as a portion of a spiral membrane (Entz, Eranze, Ehrlich). It is into this space that the food particle drops when it has reached the base of the collar. It is then sealed up in it, so to speak, as the wave of contraction passes on, by the return of the body-surface to close apposition to the envelope above it. Being now interposed between the body and the mucous envelope, it appears to lie in a vacuole in this situation; and it is eventually pressed into the interior of the body when, by a continuance of the amoeboid movement, the body again moves into close contact with the mucous envelope over the area occupied by this apparent vacuole. There are normally two contractile vacuoles situated at different levels and on opposite sides of the posterior half of the body. Entz and his school are wrong in interpreting one of these as a so-called ‘gullet vacuole ‘at which food is said to be ingested. No individuals have as yet been seen that show either division, encystment, or conjugation.