bluuebunny/crossref_metadata_2025_split huggingface dataset:
Is the Trophoblast of Hypoblastic Origin as Assheton will have it?
Authors: Hubrecht A. A. W. 
Published: April 2021

ABSTRACT
In the ‘Quarterly Journal of Microscopical Science’ there has lately appeared (vol. 54, part 2) an article by my friend Assheton, in which he points out certain objections which he feels inclined to raise against some of the views that were developed by me in a contribution to the fifty-third volume of this Journal, entitled “Early Ontogenetic Phenomena in Mammals.”
On Merlia normani.a Sponge with a Siliceous and Calcareous Skeleton
Authors: Kirkpatrick R. 
Published: April 2021

ABSTRACT
A good deal of the work in connection with the following investigation was done at the Lister Institute, in the laboratory of Professor E. A. Minchin, and I take this opportunity of thanking him for the continual help and instruction which he very kindly gave me in methods of technique.
Two abnormal Plutei of Echinus, and the light which they throw on the Factors in the normal development of Echinus
Authors: MacBride E. W. 
Published: April 2021

ABSTRACT
The present paper deals with two remarkable larvæ, the first a larva of Echinus miliaris obtained in a culture reared from eggs fertilised in the Zoological Laboratory of the Imperial College of Science and Technology, and the second a larva of Echinus esculentus obtained in a culture of eggs fertilised in the Laboratory of the Marine Biological Station at Plymouth. The second and more interesting specimen I owe to the kindness of Mr. de Morgan, by whom the culture in which it appeared was instituted.
Studies on the Development of Echinoidea: II. The Early Larva of Echinocardium cordatum and the Result of Crossing this Species with Echinus esculentus
Authors: Macbridc E. W. 
Published: April 2021

ABSTRACT
The results recorded in this paper were obtained during two months’ sojourn at the Biological Station of the West of Scotland Marine Biological Association at Millport last summer. A preliminary account of the same has already been published in the ‘Proceedings of the Royal Society ‘(16).
On Paternal Characters in Echinoid Hybrids
Authors: Shearer Cresswell , De Morga Walter , Fuchs H. M. 
Published: April 2021

ABSTRACT
Last autumn we published a paper (12) giving a brief summary up to date of some three years’ work on the hybridisation of Echinoderms. The experiments were made with the three species of Echinus found at Plymouth. Froma study of the late larval characters of the pure forms and of the hybrids we arrived at the conclusion that the inheritance of these characters was invariably maternal—that is to say, that the late larval hybrid always resembles its mother. Since the date of the publication of our preliminary paper we have continued our experiments, and have had occasion to repeat all our crosses. To our surprise, however, the behaviour of some of the hybrids has differed greatly this season from that of previous years. In late larval life some of the hybrid crosses have shown as strictly a paternal inheritance as in previous years they showed a maternal one. It may therefore be of interest to other investigators in this field of work if we publish a short account of these new facts before the completion of our full paper.
Herpyllobius arcticus
Authors: Haddon Kathleen 
Published: April 2021

ABSTRACT
Among parasitic copepods Herpyllobius is remarkable for the extreme degeneracy attained by the adult male and female, both of which are entirely devoid of appendages. The female has a globular body 2 to 4 mm. long, which, bears two large egg-sacs. It is attached to its host, a polychæte worm, by means of a chitinous fixing organ, through this there protrudes into the worm a mass of vacuolated tissue, recalling in its structure and nutritive function the root system of the parasitic Rhizocephala amongst the Cirri-pedes. It seems hardly likely that an endoparasitic stage is included in its life-history, but of this we are entirely ignorant. The adult males have a sac-like body, which remains enclosed in the last larval skin; they live attached to the body of the female in the-region of the genital apertures.
Metameric Segmentation and Homology
Authors: Goodrich Edwin S. 
Published: April 2021

ABSTRACT
In two recently published papers on the development of the fins of fish and on the segmentation of the head of Amphibia (12, 15), I had occasion to discuss incidentally the segmental relations of homologous organs, and to point out that, in the Vertebrates at all events, corresponding parts must be considered as fully homologous although occupying different segments of the body. In this paper I shall not attempt to define the nature of segmentation nor trace its origin, but shall merely try to show that a practical definition of the homology of an organ must not depend on its position in the series of segments. The subject of metameric segmentation has been very clearly dealt with by Sir E. Ray Lankester in articles on the Arthropod and Metamerism in the tenth and eleventh editions of the ‘Encyclopasdia Britannica’ (reprinted in vol. 47 of this journal). While giving a comprehensive review of the whole question of metamerism, he states thirteen “laws,” or general propositions, with most of which what follows will be found in complete agreement. But, in spite of the results of Fiirbringer (9, 10) from anatomical investigations, of Bateson (1) from observations on variation, and of others, there is, I think, a reluctance on the part of many anatomists to give up the idea that true homology depends on segmental correspondence. For instance, when discussing the homology of the occipital condyle in the Amphibia and the Amniota, we are asked on what segments they occur, it being implied, if not expressly stated, that if they are not on the same segment they cannot be homologous.
On a Remarkable New Type of Protistan Parasite
Authors: Woodcock M. , Lapage G. 
Published: April 2021

ABSTRACT
In the course of a study of the flagellates, which, develope in simple cultures of goat’s dung, we were afforded recently the opportunity, by the kindness of Drs. E. H. Ross and J. W. Cropper, of examining the contents of the rumen and other parts of the digestive tract of a goat, with a view to ascertaining what flagellates occurred in the active condition in the goat. The results of our observations in this connection will be dealt with in another memoir. The object of this communication is to describe certain remarkable parasites which we found, which appear to be of a nature quite distinct from any other protist of which we are aware. These parasites occur under two characteristic forms, which we have distinguished respectively as crescents and ovals. We are strongly inclined to regard these two principal types as being different phases of one parasite. We have examined, up to the present, six goats, and in the rumen of each, either the crescents, or the ovals, or both forms have occurred in enormous numbers—far exceeding those of the ciliates or ordinary flagellates present. A comparison of the occurrence of the two forms is given in the following table :
On the Anatomy of Ascaris (Atractis) Dactyluris
Authors: Macalister Alexander 
Published: April 2021

ABSTRACT
As the attention of the Members of the Natural History Society of Dublin has been of late directed to the consideration of the group of Entozoa, I think it might not be uninteresting to communicate a few anatomical facts with regard to the structure of a species of intestinal worm which has lately fallen under my observation. While engaged in examining the anatomy of Testudo græca, I was surprised to find that the alimentary canal in all the individuals which I dissected was filled with worms in large quantities, in fact, that entozoa constituted more than half their faecal contents ; of these there were several species, but that which was most numerous was the small, white, usually straight, and somewhat shuttle-shaped Ascaris dactyluris, first discovered by Bremser, and named by Rudolphi. The species is described by the latter naturalist in his ‘Synopsis Entozoorum,’ pp. 40272, as “Ascaris dactyluris capite nudo, corpore utrinque æqualiter attenuate, caudo fæminæ longa subulata, maris apice brevis obtuso depresso ante quern spicula passim substantia passim egressa vasa in vaginam fimbriatam.” In his subsequent description he refers to it as being found in great abundance ; he obtained “multa millia specimina ut maxima fæcum pars iisdem constaret/’ exactly according with my own experience as stated above ; he likewise describes it as being from two to two and a half lines long, with a three-val ved head ; a straight, narrow œsophagus, which is longer in the male than in the female, a subglobose stomach, and elliptic oblong ova, 3ach with a large and obscurely divided nucleus. There are several points of greater or less importance which he has omitted in his description, but on the whole these characters ire very distinct. Dujardin, in the appendix to his work on ‘Intestinal Worms,’ refers to this animal, and states his opinion that it should be separated from the genus Ascaris on account of its obscurely bi- or trilobate mouth and its unequal spicula ; he does not enter into any further details respecting its structure, but expresses his regret at not having been able to fulfil his original intention of thoroughly examining its internal organization. A few notices of this species likewise occur in Siebold’s ‘Anatomy of Invertebrates,’ but, with these exceptions, I am not aware of there being any special anatomical description of this creature extant.
Observations and Experiments with the Microscope on the Effects of Prussic Acid on the Animal Economy
Authors: Shearman Ralph Thomas 
Published: April 2021

ABSTRACT
Every year as it passes away leaves behind it additional testimony to the fact that the microscope is advancing to occupy a position of importance in medical practice equal to that which the stethoscope has attained ; and I feel satisfied that ere many more years have passed the regular employment of the microscope, as a means of diagnosis, will be maintained and duly acknowledged. The slow but steady progress which the use of this instrument has made in the hands of the medical profession should tend to point rather to the important nature of the results to which it is destined to lead us, than to accepting the doubts of some who occasionally assail its employment, and are unable or unwilling to avail themselves of its powers.
On the Anatomy of Conus tulipa, Linn., and Conus textile, Linn
Authors: Shaw H. O. N. 
Published: April 2021

ABSTRACT
SINCE 1895, few workers on the anatomy of mollusca have devoted their attention to the genus Conus. In that year Dr. Bergh (3) published an extensive memoir on a large number of species in this genus, and his work may be considered as the most complete, and embracing the greatest number of. species examined, though his description of each species was not exhaustive. Troschel (20) devoted most of his attention to the radulae of the different genera and species of which his excellent work is composed, and although he gives a certain number of figures with descriptions of various anatomical points, these latter are for the most part of rather a crude and diagrammatic kind.
A Further Study of the Mitotic Spindle in the Spermatocytes of Forficula auricularia.
Authors: Meek C. F. U. 
Published: April 2021

ABSTRACT
The length of the spindle at the stage immediately preceding the conclusion of the primary spermatocyte metaphase is not a constant. The length of the spindle at the conclusion of the primary spermatocyte metaphase is not a constant, and is sometimes smaller than that observed at the stage immediately preceding the conclusion. The length of the spindle in the early primary spermatocyte anaphase is not proportional to the amount of chromosome divergence, and is sometimes smaller than the lengths observed at the stages mentioned in (1) and (2). The volumes of the primary spermatocyte cells vary in the metaphase. The length of the spindle at the conclusion of the primary spermatocyte metaphase is not proportional to the volume of the cell. The length of the spindle at the stage immediately preceding the conclusion of the secondary spermatocyte metaphase is not a constant. The length of the spindle at the conclusion of the secondary spermatocyte metaphase is not a constant, and is sometimes smaller than that observed at the stage immediately preceding the conclusion. The length of the spindle in the early secondary spermatocyte anaphase is not proportional to the amount of chromosome divergence, and is sometimes smaller than the lengths observed at the stages mentioned in (6) and (7).
Memoirs: The Chorda Tympani and Middle Ear in Reptiles, Birds, and Mammals
Authors: GOODRICH EDWIN S. 
Published: April 2021

A comparison of the development of the various structures of the middle-ear region in the lizard, duck, and mammal, shows a remarkable uniformity in their origin and relation. The first gill-pouch separates off from the epidermis from below upwards; at its dorsal edge is an epiblastic proliferation contributing to the geniculate ganglion. The tympanum is formed between the outer epidermis and an outgrowing diverticulum of the hinder lower region of the first gill-pouch. The chorda tympani is a post-trematic branch of the facial nerve, developing behind the first or spiracular gill-slit, and passing down to the lower jaw between the tympanum and the closing spiracle. The relation of these parts to the skeleton and blood-vessels is (with the exception mentioned below) constant throughout the Amniota, and is only intelligible on the view of Reichert that the proximal region of the columella corresponds to the stapes, the quadrate to the incus, and the articular to the malleus.
In the chick the chorda tympani develops as a pre-trematic branch of the facial nerve from its first appearance. In adult gallinaceous birds the chorda passes down directly from the geniculate ganglion in front of the tympanic cavity. This exceptional position is probably due to some secondary modification at present unexplained.
The Placenta of a Lemur
Authors: Jenkinson J. W. 
Published: April 2021

ABSTRACT
Our knowledge of the placentation of the lemurs begins with the publication, in 1875, by A. Milne-Edwards and A. Grandidier, in their Historio naturelle des Maminifères de Madagascar/ of an account of the placenta in Propithecus and some other forms.
Notes on the Morphology of Bathynella and some Allied Crustacea.
Authors: Calman W. T. 
Published: April 2021

ABSTRACT
The recent re-discovery of Bathynella nutans by P. A. Chappuis (1914A, 1915)1 throws welcome light on one of the most remarkable of living Crustacea. In the thirty years that had elapsed since its first description by Vejdovsky (1882), from two specimens found in a well in Prague, this minute form had not been obtained by any other naturalist. Some eighteen years ago a re-examination of the solitary remaining specimen enabled me, in spite of its poor state of preservation, to add some details to Vejdovsky’s account, and led me to the conclusion that it was allied to An aspides (Caiman, 1899). The scantiness of information regarding it, however, has caused most writers who have had occasion to refer to Bathynella in text-books or elsewhere to suspend judgment as to its affinities, and the late Geoffrey Smith (1909) omitted it altogether from his revision of the Anaspi-dacea. The detailed account of its structure now provided by Chappuis from the specimens found in Switzerland entirely confirms my earlier conclusions as to its systematic affinities, and enables us to say that Bathynella is undoubtedly a degenerate member of the Syncarida, a group of Crustacea which has persisted from Carboniferous times, and of which the only other living representatives are found in Australia and Tasmania.
Polyembryony in Parasitic Hymenoptera : A Review.
Authors: Gatenby J. Bronté 
Published: April 2021

ABSTRACT
Among the specially remarkable facts in the study of embryology that of polyembryony or germinogony in Parasitic Hymenoptera is not the least noteworthy. Polyembryony consists in the production from one single egg, by a process of gemmation, of a large number of separate embryos. Polyembryonic species of Hymenoptera are known from the Chalcididæ and the Proctotrypidæ ; many of these insects are jet black or brownish creatures about 1 or 2 mm. in length, with gaudily sheeny wings and bodies ; in many cases they are so small as to be almost invisible to the naked eye, in others these insects are much larger, but British species above 5 mm. in length are not common.
The Pseudopodia of the Leucocytes of Invertebrates
Authors: Goodrich Edwin S. 
Published: April 2021

ABSTRACT
It is to Wharton Jones that we owe the first comprehensive account of the leucocytes in the various groups of Invertebrata : in an important paper, published in 1846 (6), he described and figured them as of “stellate appearance,” and sometimes as shooting out “cilia-like processes.” Since then numberless authors have studied these cells and pictured them as provided with free outstanding pseudopodia. Evidence is brought forward in this paper that the spiny appearance of leucocytes is of the nature of an optical illusion or due to changes taking place under abnormal conditions, that freely projecting fine processes are seldom, if ever, produced in the fluids of living invertebrates, and that the pointed pseudopodia so often figured are merely the optical sections of delicate, more or less folded films.
On the Classification of Actiniaria: Part I.—Forms with Acontia and Forms with a Mesoglœal Sphincter
Authors: Stephenson T. A. 
Published: April 2021

ABSTRACT
Whilst working out recently the species contained in two collections of Actiniaria (the “Terra Nova” collection (79)1 and one made by the Irish Fisheries Department (80)) , I have been led to develop certain views on Actinian classification. Some of the families of Actiniaria are defined by only a small number of the more important characters possessed by the contained forms, with the result that some of them (e. g. Uyanthidæ, Sagartiidæ, Paractidæ) represent not so much families as series of forms, each series including a number of animals which differ among themselves in ways so important as to be fundamental, although presenting a few common features. This arrangement neither represents the natural affinities of the genera nor does it throw much light upon their evolutionary history. It is often difficult also to allocate new species and genera to their correct position, because in a good many cases sufficiently precise generic definitions have not been arrived at. I have therefore thought it would be the best thing to set out for what they are worth the ideas I have developed during the course of my work. I have as yet applied them in detail to only one particular portion of the Actiniaria, and that application constitutes the following paper. I have begun with the group of forms belonging to the Actiniina which possess acontia or mesoglœal sphincters, because the collections I have been working at happened to present a preponderance of those forms ; I am also well acquainted with some living members of it. I am hoping in due course to work out schemes on similar lines for the classification of those Actiniina not included in the present paper and of the Stichodactylina. As yet, however, I have made only a beginning on the two latter groups, so am publishing the finished section at once. More work on these two groups may throw fresh light on various Actinian problems, but is not very likely, I think, to affect the section dealt with in this paper to any extent.
The Eye of Peripatus.
Authors: Dakin William J. 
Published: April 2021

ABSTRACT
The first description of the minute structure of the Eye of Peripatus was given by Balfour (1) in his memorable paper on the anatomy of Peripatus capensis. So far as I am aware nothing has been added to our knowledge of the structure since that date, despite the advances in microscopical technique, and the rather therough investigation of invertebrate visual organs. Other arthropod eyes have received considerable attention, and this seems strange at first because a comparison of the Peripatus eye with that of other arthropods should be highly interesting by reason of the phyletic position occupied by the Onychophora.
Studies on Insect Spermatogenesis: V. On the Formation of the Sperm in Lepidoptera
Authors: Bowen Robert H. 
Published: April 2021

ABSTRACT
In a paper published several years ago by Gatenby (1917 a) an account of sperm formation in Lepidoptera was given, certain features of which departed rather widely from the results of previous workers on similar material. Particularly interesting from my own point of view were the descriptions of the origin of the acrosome and the history of the mitochondria (‘macromitosome’ or nebenkern) in the spermatid, these matters having proved especially difficult to elucidate in the Hemiptera upon which I had resumed work early in 1919. As this work progressed, it became increasingly evident that the facts in the Hemiptera (and in other forms which I have studied subsequently) did not agree with certain important features of Gatenby’s account, and aroused the suspicion that perhaps the facts in the Lepidoptera might be open to a somewhat different interpretation. I decided accordingly to put up some lepidopteran material for purposes of comparison, and during the last three years this has been done whenever opportunity offered. Considerable difficulty was encountered, due to the impossibility of accurately determining the age of pupae from their external appearance, and a proper range of preparations was therefore not easy to obtain. Certain stages are in fact still incomplete, but the general features are now sufficiently clear to permit comparisons with other insects and it did not seem worth while to pursue the matter further at present. This paper will deal, therefore, only with the mitochondria and Golgi apparatus (‘acroblasts’), and with them particularly in the older spermatids.
On Sexual Differentiation In The Infusoria
Authors: Dogiel V. A. 
Published: April 2021

ABSTRACT
The object of this preliminary note is to describe a very curious type of conjugation which may throw light on the process of sexual differentiation in the Infusoria—a type leading from conjugation between two hermaphrodite individuals to copulation between male and female specimens. In his very lucid account of the genetics of the Ciliata, C. Dobell (1914),x with good reason, points out that in cases of typical conjugation both the conjugants are to be looked on as hermaphrodites which are performing cross-fertilization. Only in Vorticellids there are males and females, and the sexual process changes to copulation, while the dwarf-like male perishes after fertilizing the larger female. In other Ciliata there are no well-proved cases of sexual differentiation of the conjugants, although some hints at it are to be found in the works of Cull, Doflein, and Enriques. Doflein states that the conjugants of the same pair in Paramecium putrinum differ very much in size, a feature which he is ready to attribute to sexual differentiation. Enriques relates of Chilo don that the conjugants, which are very much alike at the beginning of conjugation, become differentiated into a longer and a shorter one during the process of conjugation. The meaning of such conjugants—termed by Enriques ‘male and female hemisexes ‘—remains obscure, as also the extensive discussion of the author on the subject of sexual differentiation. The observations of Cull on ‘incipient sexuality ‘in Paramecium proved to be erroneous (Jennings and Lashley), and need no further mention. But in this paper I propose to describe a case of conjugation in the Ciliata where the members of a pair show very marked differences, which may have a relation to sex.