bluuebunny/crossref_metadata_2025_split huggingface dataset:
Studies in the Experimental Analysis of Sex
Authors: Smith Geoffrey , Hamm A.H 
Published: April 2021

ABSTRACT
It has long been known that the presence of Strepsipterous parasites on solitary bees and wasps may exert a remarkable influence on their hosts, and the paper by Professor J. Pérez in 1886 (1), gave a full account of the effect of Stylops melittæ on the bees Andrena, which must always be referred to as a classical contribution to the study of parasitic castration. Although many authors have subsequently written on these parasites, the observations of Monsieur Pérez remain unsurpassed for fulness of detail and interest, and we are indebted to the veteran entomologist for additional information which he has kindly put at our disposal in answer to inquiries. The re-examination of the subject, which is undertaken here, seemed desirable, not so much for the purpose of bringing new facts to light, but for confirming reported facts and collating them with the newly acquired results on parasitic castration brought about by Sacculina, since the effect of Stylops on its hymenopterous hosts seemed to be parallel to that of Sacculina on crabs,and yet to differ from it in many important respects. The Strepsipterous parasites differ from Sacculina in that they have the sexes separate, whereas Sacculinais hermaphrodite, so that we can test whether the sex of the parasite has any influence on the effect excited. Moreover, it is clear that in certain cases the female host is induced to assume certain male characters as the result of parasitic castration by Stylops, an effect which is never observed in the case of Sacculina, and which requires careful examination. We have been able to study a large number of stylopised bees of various species, but the most fruitful material consisted of a large colony of heavily stylopised Andrena nigroænea, established in a grassy bank close to the University Muséum, which was kept under observation for several years and afforded us a rich collection. The following observations on the structure and history of the parasite are based on the bees taken from this colony.
Studies on Parasitic Protozoa.
Authors: Mackinnon Doris L. 
Published: April 2021

ABSTRACT
In 1911, I recorded from the intestine of trichopterous larvæ, a slipper-shaped flagellate with a relatively enormous cytostome. I named the organism Embadomonas, and pointed out that it showed affinities with Chilomastix Alexeieff, 1911 (Syn. Macrostoma, Alex., Tetramitus Alex.), from which it differed in its general form, and in the number of the flagella. The species from trichoptera I called E. agilis.
The Development of Alcyonium digitatum, with some notes on the Early Colony Formation.
Authors: Matthews Annie 
Published: April 2021

ABSTRACT
The fertilised eggs segment in various ways, but typical morulæ always result. When the sixteen cell stage again divides to produce the thirty-two celled embryo, delamination occurs, and from now onwards the larva is two-layered. The morula at the twentieth hour begins to undergo a series of contortions which last from the first to the third day. This solid contorted stage is here termed the pre-planula, as it passes on into the hollow planula stage. The pear-shaped planula, while swimming, exhibits characteristic “planarian-like” movements, and on the fourth free-swimming day (the seventh day of development) it settles down by the broad anterior and aboral pole. The settled larva soon flattens, assuming a mound-like shape, and ou the second day of fixation eight mesenteries grow out simultaneously into the coelenteron from the base of the lateral wall. The cœlenteron is identical with the hollow entrai space in the endoderm of the planula. The mesenteries, arranged in four distinct pairs, grow simultaneously and rapidly along the lateral walls and attached base, and soon nearly meet on the basal and oral surfaces of the polyp. Many round cells now appear at the base of the columnar ectoderm. Mesoglœa is at this time secreted by the endoderm, and flows round the above-mentioned round ectoderm cells, cutting them off either singly or in groups. These isolated ectoderm cells produce either nematocysts or spicules, the spicules appearing soon after the mesenteries. Early on the third day eight simple hollow tentacles grow out, alternating with the mesenteries, and encircling the oral surface. Later on the third day the stomodæüm and moufli arise by the appearance of a rapidly deepening invagination of the oral surface, in the centre of the circle of tentacles. Yolky detritus is still present in the coelenteron. On the fourth day the base of this invagination degenerates, and so the coelenteron communicates with the exterior. While the mouth invagination is still in process of formation, the endodermic portion of the mesenteric filaments arises on the six ventral mesenteries by a proliferation of cells on the upper part of the free edge. On the fifth day the ventral mesenteric filaments are completed by strap-like ectodermic downgrowths from the stomodæum over the endodermic thickening on each mesentery. On the sixth day the dorsal mesenteric filaments arise. The dorsal and ventral mesenteric filaments appear homogeneous in origin, though of diverse function. On the seventh day the eight filaments reach about half way down the free edges of their respective mesenteries. Further development consists of elaboration of the organs already present. At the end of the third week the first bud is formed, and the solitary polyp becomes a young colony by stolonal gemmation. The young colonies were successfully fed in the laboratory on larvæ and adult individuals from colonies of Lepto-clinum and Botryllus.
On a Larval Actinian Parasitic in a Rhizostome
Authors: Badham C. 
Published: April 2021

ABSTRACT
Our knowledge of the medusophilous larval Actinians has been summarised by Haddon (1) and by McMurrich (2). The last-named author says: “The available evidence seems accordingly to point strongly in favour of the various medusophilous forms being the young stages in the development of Peachia rather than Halcampa; but a direct linking-up of the immature examples of Bicidium1 with their respective adults is necessary to settle the question.”
On the Development of the Segments of the Head in Scyllium
Authors: Goodrich Edwin S. 
Published: April 2021

ABSTRACT
The object with which this work was undertaken was to describe the development of the skull in Scyllium and the relation of its elements to the general segmentation of the head, more especially in the occipital region. But it soon became evident that our knowledge of the segmental composition of the head in Elasmobranchs is still in a very unsatisfactory condition, and that a re-investigation of the whole question was necessary. In addition, then, to an account of the development of the skeletal segments, a short history of the mesoblastic somites is given, and incidentally of certain points in the development of the nerves and other structures in the head region.
Reproduction by Transverse Fission in Phoronopsis
Authors: Gilchrist J.D.F. 
Published: April 2021

ABSTRACT
The occurrence of asexual reproduction in the Phoronidea, though apparently an easy matter to determine, has not proved to be so. Species of Phoronis occur in groups of closely associated individuals or colonies, and it has often been observed that they have the power of casting off and rapidly regenerating the whole of the lophophoral or distal end of the body. Several observers have noted the occurrence, and the process of regeneration has been described in detail by Schultz, who also found that regeneration occurred in both parts of a Phoronis cut in two. Though the naturally detached part can be readily kept under observation, it was never found to develop into, a new individual, and this may be the reason why no suggestions were made of the possible reproduction of the animal by simple division of the body. In 1907 Selys-Longchamps (7), in repeating the experiments of Schultz, came to the conclusion that natural division of the body probably does occur, and that the animal reproduces in this way. It was not, however, until 1917 that any definite proof of this suggestion was brought forward, when Harmer (3), in his rediscovery of Phoronis ovalis, found definite evidence, which seems to place it beyond doubt that such an occurrence does take place.
On a Species of the Crawling Medusa, Eleutheria, from the Cape of Good Hope (Cnidonema capensis, g. et sp. n.) and the Southern Eleutheriæ
Authors: Gilchrist J. D. F. 
Published: April 2021

ABSTRACT
A species of “Eleutheria” is found in fair abundance at certain times and places at the Cape of Good Hope. It can readily be kept in confinement, and some of its habits are noted. The chief characteristics of the species are described and compared with those of other southern species. Its hydroid form has been found, and proves to be very similar to that of Cladonema (Stauridia), not of Eleutheria (Clavatella). It differs, however, from Cladonema chiefly in the absence of oral tentacles, and a new genus (Cnidonema) is proposed for the reception of this and probably all the other southern Eleutheria, the hydroid forms of which, however, are not yet known.
The Terminology of Parthenogenesis
Authors: Lankester Sir Ray 
Published: April 2021

ABSTRACT
The word “parthenogenesis “has become established in biological science to signify the production of offspring by a virgin mother. The term does not embrace reproduction by buds or by fission, but refers to parentage by a mother who produces egg-cells identical in character with those which, in the vast majority of instances, fuse with male sperm-cells before proceeding to develop. In those instances which are distinguished as instances of “parthenogenesis/’ the egg-cells proceed to develop without fusion with the male reproductive element or sperm-cell.
Observations on an Intra-nucleolar Body in Columnar Epithelium Cells of the Intestine
Authors: Carleton H. M. 
Published: April 2021

ABSTRACT
The presence of one or more intra-nucleolar bodies in the columnar cells of the intestinal epithelium in the frog and cat has been demonstrated. To these inclusions the term “nucleolinus,”originally introduced by Haeckel, has been applied. By a modification of the Cajal technique for the Golgi apparatus, the nucleolinus has, in the frog’s intestine, been impregnated in a perfectly specific manner. The presence of nucleolini both in karyosomes (e.g. cat)and in plasmosomes (e.g. frog) in the columnar intestinal cells shows that they are not restricted to one of these types of nucleolus. Evidence has been adduced showing that division of the nucleolus (plasmosomes) in the resting cell is in all probability accompanied by fission of the nucleolinus. During mitosis the nucleolinus has been shown apparently to divide, a portion or portions of it being distributed to each of the daughter-nuclei. This is in contrast to the behaviour of the nucleolus (plasmosome), which disintegrates during cell division. The presence of the nucleolinus has been confirmed in the columnar cells of the intestinal mucosa in both the frog and the cat by other and simpler methods than the Cajal technique. The significance of the apparent continuity of the nucleolinus has been very briefly discussed.
On the Pharyngeal or Salivary Gland of the Earthworm.
Authors: Keilin D. 
Published: April 2021

ABSTRACT
It is well known that the dorsal wall of the pharynx in all earthworms is much thickened, and forms a real pharyngeal bulb, which bulges prominently into the coelomic cavity. By dissection from the dorsal surface of the earthworm, this pharyngeal bulb can be easily seen with an ordinary lens and, in the larger specimens, even with the naked eye. It is richly vascularized and its surface is irregular and tabulated. In longitudinal median section the pharyngeal bulb is seen to be composed of the three following portions : (1) an external epithelial sheath, (2) a median mass of musculo-vascular tissue, and (3) an internal portion composed of aggregates of deeply-staining cells.
Further Studies on Restitution-bodies and free Tissue-culture in Sycon.
Authors: Huxley Julian S. 
Published: April 2021

ABSTRACT
In a previous paper (Huxley, 7) I showed that the remarkable phenomena of regeneration from dissociated cells, first observed by H. V. Wilson (15) in monaxonid sponges, later extended by him (16) and by de Morgan and Drew (4) to coelenterates, could be studied in a simpler and more satisfactory form in hoterocoelous calcareous sponges than in any other types investigated. I further showed that, by certain metheds, restitution-bodies composed entirely or almost entirely of collar-cells could be produced, and that these assumed a form quite unlike anything found in normal sponges, but with a resemblance to a Choanoflagellate colony. Simple excess of collar-cells, or, apparently, larger masses composed almost entirely of collar-cells, led to the formation of what I called choanocyte blow-outs—a part of the solid mass becoming blown out to form the segment of a collar-cell sphere.
The Proboscis of the Syllidea. Part I. Structure.
Authors: Haswell W.A 
Published: April 2021

ABSTRACT
The proboscis of the Syllidea (here taken as comprising all that part of the digestive tube lying in front of the intestine) is made up of five parts (fig. 6), which are all (with the exceptions presently to be noted) sharply marked off from one another. These will be referred to here as (1) the buccal chamber, (2) the pharynx, (3) the proventriculus, (4) the ventriculus, and (5) the post-ventriculus with a pair of caeca, appended to it.
The Life-history of Melicertidium octo-costatum (Sars), a Leptomedusan with a theca-less Hydroid Stage
Authors: F. Gemmill James 
Published: April 2021

ABSTRACT
This -well-known medusa (fig. 19) is classified among the Thaumantiadae, and is characterized by the presence of eight ‘radial’ canals on which the gonads are developed. The marginal tentacles are numerous (up to 140) and of unequal size, larger and smaller ones alternating more or less regularly. There are no lithocysts, cordyli or ectodermal ocelli. The manubrium is short, the mouth four-angled and without oral tentacles. The medusa has a fairly wide distribution in the North-east Atlantic ranging from Bergen to Falmouth. (See E. T. Browne, 4, for details and a discussion of the nomenclature.) The hydroid, as I have ascertained by rearing the eggs, proves to be a hitherto undescribed species identical with one which has been noted for several years (with a year’s interval of absence) growing abundantly and spontaneously in the tanks at the Millport Biological Station.
On the Classification of Actiniaria.: Part II.—Consideration of the whole group and its relationships, with special reference to forms not treated in Part I1
Authors: Stephenson T. A. 
Published: April 2021

ABSTRACT
It has been necessary, on account of the length of the present paper, to confine Part II to discussions; the definitions of families and genera involved, on the lines of those already given in Part I, will be printed in another issue of this Journal as Part III, which will also contain a list of literature and an index to genera covering Parts II and III. The list of literature will be additional to that printed in Part I, and any numbers given in brackets in the following pages will refer to the two lists as one whole.
The Development of the Sea Anemone Bolocera Tuediae (Johnst.)
Authors: Gemmill Janies F. 
Published: April 2021

ABSTRACT
Bolocera tuediae was recorded and described from deep water near Berwick by Johnston (11) in 1832. Gosse described it more fully in 1860 (10, p. 185) and the following is his summary of its characters: ‘Base adherent, not much exceeding the column. Column pillar-like, the diameter and height sub-equal; surface generally very smooth, studded with warts remotely scattered. Disc smooth, circular in outline, not overlapping the column. Tentacles short, thick, constricted at foot, obtusely pointed, longitudinally furrowed, flexuous and motile, easily separated, not retractile. Mouth raised on a cone. Stomach capable of being greatly protruded.’ The tentacles are, however, moderately long and slender when fully extended during life.
The Early Development of the summer egg of a Cladoceran (Simocephalus vetulus)
Authors: Cannon H. Graham 
Published: April 2021

ABSTRACT
1. Each egg is laid as a yolky mass of a foam and later forms a primary egg-membrane.
2. Cleavage is completely superficial and apparently indeterminate.
3. The first differentiation of the blastoderm is the appearance of a group of vacuolated yolky cells on the ventral side of the embryo which are called the ventral mass.
4. This subsequently differentiates into a few large cells with very large nuclei which form the genital rudiment, surrounded laterally and posteriorly by ectomesodermal cells, and anteriorly to this a mesendodermal mass of cells from which arises the mesendoderm.
5. The genital rudiment surrounded laterally and posteriorly by inwardly growing ectomesodermal cells invaginates and becomes internal by the lips of the invagination growing together and fusing.
6. The mesendoderm grows backwards as a solid mass of cells, which later spreads out flat and becomes indistinguishable from the laterally-lying mesoderm, and from this layer the endoderm separates as a solid rod in the median plane.
On the Labral Glands of a Cladoceran (Simocephalus vetulus), with a description of its mode of feeding
Authors: Cannon H. Graham 
Published: April 2021

ABSTRACT
Leydig (12) in 1860 was the first worker to point out that the possession of labral glands is common to all the Cladocera. In 1846, however, Schödler (16) had observed that in the labrum of Acanthocercus there exist paired glandular bodies; he states, ‘Im sog. Labrum (des Acanthocercus) glauben wir ein paar rundliche, fast nierenformige Conglomerate als drüsige Körper (vielleicht als Speicheldrüsen, glandulao salivales) ansprechen zu müssen’. Claus (3) in 1876 mentioned these glands in his work on the anatomy of Daphnids, and later Cunnington (5) in 1903 described them in Simocephalus sima (Simocephalus vetulus).
The Segmentation of the Head in Squalus acanthias
Authors: de Beer G. Rylands 
Published: April 2021

ABSTRACT
There are two views with regard to the segmentation of the head. One has arisen out of Balfour ‘s (1) pioneer work, the other is due to Van Wijhe (18). They both agree on many points, and the difference between them lies in the interpretation of the numerical relations of the different segmented structures, as pointed out by Goodrich (8). In order that they may be compared, a short account of these views will now be given.
Some Notes on the Gametogenesis of Ornithorhynchus Paradoxus
Authors: Gatenby J. Brontë 
Published: April 2021

ABSTRACT
In this paper I have described in as much detail as was possible the oogenesis of the duck-billed platypus of Australia. Owing to the unique position of the Prototheria, any new facts with regard to their germ-cells is sure to be of value. I must take this opportunity of thanking Professor J. P. Hill, F.R.S., for allowing me to study his material of Ornithorhynchus, without which I could not have published these notes.
Note on the Comparative Effects on Tissues of Isotonic Saline and Distilled Water when used as Solvents for Mercuric Chloride and Formol in Histological Fixation
Authors: Carleton H. M. 
Published: April 2021

ABSTRACT
Should a simple fixative such as mercuric chloride or formol be dissolved in normal (i. e. isotonic) saline or in water ? Curiously enough, observations are lacking on this simple but fundamental point.
Cannibalism in Amoeba vespertilio (Penard)
Authors: Lapage Geoffrey 
Published: April 2021

ABSTRACT
This paper describes the temporary adoption by Amoeba vespertilio of cannibalistic habits. The amoebae frequently ingested, but in most cases failed to digest, other individuals of their own and also of other species (A. limax). In some cases, an amoeba, which had ingested another, might itself then be ingested by a third amoeba ; and these three might then be taken up by a fourth amoeba, so that remarkable figures, suggesting concentric fission, resulted. The victims were usually ingested while they were rounded off or sluggish, and, after extrusion, usually failed to resume their activity, although most of them developed contractile vacuoles and some showed tentative amoeboid movements. A few recovered their normal activity and resumed normal life. Amoebae, after extrusion by one amoeba, were often taken up again by other amoebae. In one case an Amoeba vespertilio was observed to chase and enclose an Amoeba limax, but the Amoeba limax subsequently escaped again. The ingested amoebae may easily be mistaken for endogenous buds, but there is less danger of their being mistaken for-parasites. No trustworthy evidence was found as to the nature of the stimulus which caused the adoption of these habits, but the question is discussed.
Some Observations upon the Development of the Teeth of Physeter macroeephalus.
Authors: Beddard Frank E. 
Published: April 2021

ABSTRACT
On the following pages I describe the nature of the tooth rudiments in the very young embryo of Physeter macro-cephalus, whose general external characters I have already commented upon and figured (Beddard, 1). Since the material upon which I have worked is, so far as I am aware, a unique specimen only inches long 4 ½ I am particularly grateful to the Curator of the Durban Museum (Mr. E. C. Chubb) for placing it in my hands and to the authorities of the Museum of the Royal College of Surgeons of England for allowing their highly skilled assistant, Mr. Steward, to prepare a series of sections for study.