bluuebunny/crossref_metadata_2025_split huggingface dataset:
Some Notes on the Mucous and Skin Glands of Arion ater
Authors: Barr R. Aileen 
Published: April 2021

ABSTRACT
The pedal gland is an internal aggregation of mucous cells, whose products form a locomotory slime track, and are expelled from the gland by ciliary action in the excretory canal of the gland, and by contractions of muscular fibres among the cells and’by the movements of the foot. The pedal gland of Arion is intermediate in position and structure between that of Limax and that of Milax. The caudal gland is an aggregation of mucous and calcic cells at the posterior end of the body. Its secretion is used, in the young stages, to form a slime thread for descent; during the period of sexual activity the slime gland becomes much more active, probably owing to the influence of the developing sexual organs. Its secretion is devoured mutually by slugs about to copulate. There is an aggregation of unicellular mucous glands on the outer side of the peripodial groove, which I propose to call the peripodial gland. This pours out its secretion on to the foot-fringe and into the peripodial groove, an open ciliated channel which carries the mucous secretion of the body down to the caudal gland. The skin of A r i o n contains mucous, calcic and pigmentary glands which are most numerous on the mantle margin and foot-fringe. The mucous cells provide a secretion all over the body, especially on any ciliated region, which keeps the integument moist. The calcic concretions are probably an excess of lime formed by the calcic cells, which in a shelled species would be employed in building up the shell. They may exercise a protective function, as do the spicules of sponges. The black pigment cells, or chromatophores, are minute irregular cells found just under the epithelial layer, and are often clustered round the blood lacunae. It is probable that the black pigment is produced as a degeneration product of the blood. The red pigment is not contained in special cells but lies in the dermal mucous glands and intercellular spaces. It is probably a compound produced by a lipochrome and the lime of the calcic cells, and it is stored in the tissues in default of a shell on which it might be deposited. It is excreted, possibly as a waste product from the body, along with the body mucus.
Hermaphroditism in Bhyscotus, a Terrestrial Isopod
Authors: Jackson Harold G. 
Published: April 2021

ABSTRACT
The Rhyscotinae are shown to be a non-parasitic hermaphrodite sub-family of terrestrial Isopods. They are protandrous, the ovaries and oviducts making their appearance as individuals approach the female phase. The male external genitalia, vesiculae seminales, vasa deferentia, and a vestige of testis are retained throughout life. The facts are discussed in connexion with other forms, and the possibility of a cyclical alternation of sexes considered.
The Rôles of the Nurse-cells, Oocytes and Follicle-cells in Tenthredinid Oogenesis
Authors: Peacock A. D. , Gresson R. A. R. 
Published: April 2021

ABSTRACT
Since Buchner’s important researches on the hymenopterous egg (1) there does not appear to have been any study, until the present one, which follows up that part of his work relating to oogenesis in sawflies (Tenthredinidae). Buchner was interested particularly in the hymenopterous accessory nuclei, and the larger picture of sawfly oogenesis was left far from complete.
The Effect of a Temperature Gradient on the Early Development of the Chick
Authors: Tazelaar Maria A. 
Published: April 2021

ABSTRACT
Owing to the difficulty of ascertaining the exact position of the embryo in the egg there was much waste of material. Hens’ eggs are not ideal for temperature gradient experiments, for the mean between the temperatures which can be used is below normal incubation temperature. The egg of a coldblooded animal would be far simpler to deal with. The part most easily affected by a temperature gradient was the area vasculosa and its blood-vessels. This was to be expected, since the size of this extra-embryonic part is not strictly limited; the arrangement of the blood system of the area vasculosa was also modified in some cases. Slight disproportion of parts was effected in some cases. The head was sometimes slightly more developed than the posterior end, and in some cases the posterior limbs were precociously developed. Differences in size between the limb buds on each side also occurred. The ratio of embryo to primitive streak was decreased considerably in the case of two embryos, treated with antagonistic gradients. In some embryos treated with a lateral temperature gradient the somites had become shifted up on the heated side. The greatest effect was obtained in an embryo whose somites of one side alternated with those of the opposite side. It is possible that this condition may be regulated after normal incubation ; results, however, were too few for certainty. The numbers used were not sufficient for the conclusive determination of the degree of regulation which experimentally treated embryos underwent. However, all late stages when examined were normal ; whether these cases were correctly treated or not it is impossible to say.
Memoirs: Lipin Secretion in the Elasmobranch Interrenal
Authors: FRASER A.H. H. 
Published: April 2021

1. The occasional occurrence of an intimate anatomical relationship between the interrenal and chromaffin tissue is described.
2. It is shown that in addition to the ordinary lobule commonly figured, the interrenal may show hypertrophied lobules, disintegrating lobules, and acini. These various histological pictures are interpreted as being various phases in a definite cycle of glandular activity, viz.:
(1) Resting lobule.
(2) Distension of lobule.
(3) Disintegration of lobule.
(4) Formation of acinus.
(5) Collapse of acinus.
(6) Reformation of resting lobule.
3. Evidence is advanced of a massive secretion of lipin into the interlobular capillaries. The importance of this phenomenon is emphasized.
4. The occurrence of melanin pigment in a minority of the glands is described, and evidence submitted of a relationship between the formation of melanin and the secretion of lipin.
Mitochondrial Behaviour during the Life-cycle of a Sporozoon (Monocystis)
Authors: Horning E. S. 
Published: April 2021

ABSTRACT
Observations show that mitochondria are capable of arising de novo in the freshly liberated sporozoite stage of the life-cycle of Monocystis. Mitochondria are present in large numbers throughout the course of the asexual phase of the life-cycle. During the conjugation of the gametocytes the rod-like mitochondria give rise to numerous spherical bodies. At fertilization the mitochondria within the gametes appear to fuse, resulting in the formation of larger clumps. At the commencement of the spore phase the mitochondria gradually decrease in numbers, and are totally absent within the mature spore. Later, the growth of the liberated sporozoite or young trophozoite is accompanied by a reformation and rapid reproduction of mitochondria. The disappearance and reformation of mitochondria during certain stages of the life-cycle may be correlated with their apparent synthetic activity.
On the Development of the Mid-Gut in the Larval Stages of Vanessa urticae (Lepidoptera)
Authors: Henson H. 
Published: April 2021

ABSTRACT
The mid-intestine of Vanessa urticae has three separate categories of cells, interstitial cells, goblet cells, and ordinary columnal epithelial cells. The interstitial cells renovate the epithelium by the addition of new cells at each larval ecdysis. There is a period at the beginning of each instar during which cell differentiation occurs (from interstitial nests). This process soon ceases. Cell division by mitosis occurs amongst the interstitial cells throughout the instar. No good evidence could be obtained that the goblet cells and columnar cells are homomorphous. The goblet cell cannot become a columnar cell because it undergoes a cycle of growth and differentiation which diverges increasingly from the columnar type. Similarly the goblet cells cannot be derived from senescent columnar cells because they are present at the time of hatching. Both are derived by independent modification of interstitial cells and are therefore dimorphous. The goblet cells contain material which is optically indistinguishable from striated border. It has been shown that in this animal the so-called merocrine method of secretion of the gut cells may not be a secretion process at all. The alternative view that the formation of ‘secretion’ vesicles is really a process of cell disintegration, due to wear and tear, or to the incidence of metamorphosis, is here favoured.
Nucleolar behaviour in the Mitosis of Plant Cells
Authors: Frew Priscilla E. , Bowen Robert H. 
Published: April 2021

ABSTRACT
The resting nuclei of Cucurbita pepo and Cucurbita maxima contain a single, spherical nucleolus that is relatively very large. Part, at least, of this nucleolus persists during nearly the entire process of mitosis. During the metaphase it lies in the equatorial plate and becomes elongated in the direction of the long axis of the spindle, to form first a cylinder and then, with further elongation, a dumb-bell-shaped structure, which finally separates into two fragments that migrate to the opposite poles of the spindle. This entire movement occurs prior to any anaphase migration of the chromosomes. The nucleolar fragments apparently are not included in the daughter nuclei during the telophasic reconstruction, but degenerate in the cytoplasm. Examination of the literature suggests that a similar process of nucleolar division probably occurs in a wide variety of plant-cells. The bearing of this type of nucleolar division on theories of the dynamics of anaphase migration of the chromosomes is briefly discussed.
The Grigarinis of Cucumaria: Lithocystis minchinii Woodc. and Lithocystis cucumariae n.sp
Authors: Goodrich Helen Pixell 
Published: April 2021

ABSTRACT
In 1906 Woodcock described an interesting gregarine occurring in the respiratory trees of Cucumaria. 1 This parasite is neogamous and so precocious is its association that normal single vegetative forms (trophozoites) have not been seen. Apparently, as Woodcock pointed out, infection takes place by spores being drawn into the respiratory trees with currents of water through the cloacal aperture—a quite exceptional method of contamination, so far as is known. The sporozoites emerging from a ripe spore probably penetrate immediately between the epithelial cells into the connective tissue of the respiratory tree wall and there pair and round off. After absorbing food and growing at the expense of the host, they encyst. The host also forms round each pair of parasites a cyst consisting of several layers of flattened cells. These spherical cysts of various sizes are the most commonly encountered stage of the parasite, and are to be seen as conspicuous opaque white spheres through the wall of the respiratory trees on opening into the coelom. Each cyst contains two nuclei, but generally no partition or other indication of a dual origin. They are quite soft and easily deformable, becoming much flattened when mounted under a cover-glass. These early stages have already been described by Woodcock, who recorded cysts varying from 17 to 2OOµ in diameter. I have been lucky enough to find still larger cysts, many containing spores, other?vise I can add little to his description. Finding nothing but vegetative stages in the respiratory trees, Woodcock was led to connect this parasite with another gregarine, Lithocystis (Diplodina, Cystobia) minchi nii, which he found in the general body-cavity. This protozoan parasite was also fairly common in the Cucumaria that I have examined, and some further description of it is given below (p. 280).
The Formation and Fate of the Operculum and Gill- chambers in the tadpole of Bana temporaria
Authors: Brock Gwendolen T. 
Published: April 2021

ABSTRACT
This work has been undertaken with the object of establishing the exact method of formation of the operculum and gill-chambers in the tadpole. It is also intended to follow up a suggestion of 0. H. Latter (1923) that branchial respiration continues after metamorphosis by means of paired apertures immediately in front of the bases of the freed anterior limbs.
The Neuro-muscular mechanism of the gill of Pecten
Authors: Setna S. B. 
Published: April 2021

ABSTRACT
The gills of Pecten have been the subject of much study, their structure being particularly described by Ridgewood (1903), Kellogg (1915), and Dakin (1909). However, there are structures of profound physiological importance present in the gills which apparently have so far remained unnoticed, while data are lacking concerning the neuromuscular mechanism which leads to a definite and orderly distribution of food material on the gill surfaces. Further, there are only casual references to the sensory reactions of the gill, without which an adequate understanding of their function is impossible. My own observations disagree with those of Kellogg (1915), who writes, ‘Extensive movements of the gills of Yoldia have been described by Drew (1899) and the writer (1890) in which organs there are well-developed muscles, but in the Pecten gill and others also capable of extensive movements such muscles are absent.’
Variation in the Histological Condition of the Thyroid Glands of Sheep with regard to Season, Sex, Age, and Locality
Authors: Lowe Esther 
Published: April 2021

ABSTRACT
Our present knowledge of the thyroid gland has been derived chiefly from the investigations of workers on the human gland. A comparatively small amount of work has been done on the thyroids of the lower animals, and this has been chiefly of an experimental nature, very little attention having been paid to the histology.
The Green Bodies of the Intestinal Wall of certain Chaetopteridae
Authors: Berkeley C. 
Published: April 2021

ABSTRACT
The green bodies in the intestinal epithelial cells of three species of Chaetopteridae, each representing a different genus, have been examined. They are very similar in the three cases and resemble those of Chaetopterus variopedatus. They are frequently motile and flagellated when separated from the intestinal tissue. They represent an infection of an organism which spreads in a flagellated condition. The organism is a flagellate probably belonging to the family Chrysocapsinae. The name Chrysocapsa chaetopteri is proposed for it.
On the unsegmented ovum of Echidna (Tachyglossus)
Authors: Flynn T. Thomson 
Published: April 2021

ABSTRACT
In this communication is described for the first time the unsegmented germinal disc of the monotreme Echidna (Tachyglossus), and measurements are also given of living intra-uterine eggs at early stages Segmentation is not initiated in Echidna until the egg has arrived in the uterus The polar bodies are much smaller than those described for Ornithorhynchus. The first is much larger than the second but, contrary to what has been reported to occur in Ornithorhynchus, remains undivided The germ nuclei, immediately before the formation of the first cleavage spindle, undergo conjugation and fusion. Contrary to what is described for Ornithorhynchus, polyspermy does not normally occur in the fertilization of the ovum of Echidna.
Development of the Sex Glands of Calotes. I. Cytology and Growth of the Gonads prior to Hatching
Authors: Simkins Cleveland Sylvester , Asana J. J. 
Published: April 2021

ABSTRACT
There are two dissimilar and opposing views regarding the origin of the sexual elements in the vertebrates in general, and these dissimilar views are held by workers upon the origin of the reproductive elements in the Reptilia as well. The provisional conjectures are these : first, the forerunners of the propagative elements, the so-called primordial germ-cells, originate outside the fundament of the gonad and migrate to that incipient structure throughout the course of early ontogenesis ; second, the definitive germ-cells arise in the gonad, concomitant with its formation from units directly derived from the germinal epithelium.
The Oogenesis of Calanus finmarchicus
Authors: Hilton Irene F. 
Published: April 2021

ABSTRACT
Three regions can be recognized in the ovary: a multiplication zone containing oogonia undergoing mitosis, a synapsis zone containing the first formed oocytes in the prophases of the maturation division, and a growth zone containing oocytes in a series of growth phases with the nucleus in a ‘resting condition ‘.
The oogonial nuclei contain two or three nucleoli—plasmosome and karyosomes. In the oocytes a single nucleolus is present; this is formed by the fusion of the plasmosome and at least one karyosome and is therefore an amphinucleolus. The chromatin in the oogonia and young oocytes is arranged round the periphery of the nucleus andis aggregated in knots (pp. 196-200).
Nucleolar extrusion begins in the young oocyte and continues throughout the growth period. It is most marked in the young oocytes and in oocytes about to undergo maturation (pp. 200-3).
In the older oocytes the chromatin is in the form of a tangled thread surrounding the nucleolus. Immediately before maturation this condenses and circular chromosomes emerge: these form tetrads (pp. 203-5).
The mitochondria are present in the oogonia and very young oocytes in the form of a cap lying upon the surface of the nuclear membrane. The mitochondrial elements spread and multiply until they surround the nucleus as a ring; afterwards they disperse and are distributed evenly throughout the cytoplasm. They swell up and finally yolk-droplets appear in their place (pp. 207-11).
Yolk-formation usually begins in half-grown oocytes, but is sometimes earlier. The formation of yolk-droplets begins at the periphery of the cell and proceeds inwards. It is suggested that yolk is formed by transformation of the mitochondria and the deposition in them of substances derived from the cytoplasm and the nucleolus. The cytoplasm is flocculent in the young oocytes, granular in the half-grown oocytes, and filled with fluid vacuoles in mature oocytes. It passes from a primary condition of oxyphily to basophily and finally back to a secondary oxyphil condition in mature oocytes (pp.211-13).
In the young oocytes deeply-staining spherical structures were seen adjacent to the mitochondrial cap. From their appearance it is possible these bodies represent the Golgi apparatus, but Da Fano fixation failed to demonstrate them. In half-grown oocytes the apparatus was visible in the complex condition at one side of the cell. As growth proceeds it passes from a complex to a diffuse condition and in mature oocytes the Golgi elements are uniformly distributed throughout the cytoplasm (pp. 213-15).
The Cranial Characters of the Brevicipitid Genus Cacosternum (Boulenger)
Authors: de Villiers C. G. S. 
Published: April 2021

ABSTRACT
The present paper is a continuation of my work on the cranial characters of the two South African Brevicipitid genera lacking the claviculo-procoracoidal arch in the pectoral girdle. The genus Phry nomerus (Noble) was discussed in a previous paper in this Journal (vol. 73), to which the reader is referred for details of technique, which was, however, slightly varied for purposes of the present research, inasmuch as double bulkstaining was resorted to. The nuclear stain, haemalum, was applied in the usual way, and after all traces of alum used for differentiation were washed out, the object was bulk-stained for twenty-four hours in a strong aqueous solution of Bismarck brown and differentiated in ordinary tap-water for forty-eight hours. I have not yet experimented with bulk-staining for connective tissue and muscle; stains recommended for this purpose are fuchsin and light green or eosin respectively. The use of van Gieson in conjunction with Bismarck brown is considered by many workers to lead to confusing results, so that pure fuchsin is recommended for connective tissue and for decalcified bone. All material was decalcified with Ebner’s solution in preference to nitric acid, which is, however, used with great success for the same purpose by Professor Stadtmiiller of Gottingen, according to a personal communication from him. The material of Cacosternum bottgeri was kindly supplied by the Director of the Transvaal Museum; Cacosternum capense was collected by the author on the Stellenbosch Flats after the first rains in May 1928. The eighteen specimens collected are the only ones known besides the type specimens collected by Mr. Rose of Cape Town. Three specimens of Cacosternum namaquense were collected by Dr. Herre of Stellenbosch University during the phenomenal Namaqualand rains of 1929; but owing to the rarity of the material, this species was not microtomized. Mr. Hewitt has recently upheld the species and recorded the existence of two specimens referable to it in the collection of the South African Museum.
The Scientific Work of Edwin Ray Lankester
Authors: Goodrich Edwin S. 
Published: April 2021

ABSTRACT
The death on August 15, 1929, of Sir E. Ray Lankester, formerly Editor of this Journal, was announced in the November number of vol. 73, 1929.1 Lankester’s long connexion, as Co-Editor, as sole Editor, and finally as Honorary Editor, with the ‘Quarterly Journal of Microscopical Science’ has already been dealt with by A. Sedgwick and W. F. R. Weldon in the complimentary number dedicated to him on the occasion of the twenty-fifth year of editorship (no. 141, vol. 36, 1894), and again on his seventieth birthday by G. C. Bourne (no. 253, vol. 64, 1919).
Observations on Dicystid Gregarines from Marine Worms
Authors: Mackinnon D. L. , Ray H. N. 
Published: April 2021

ABSTRACT
Two species of the dicystid gregarine Polyrhabdina Mingazzini have been studied in polychaete worms from Plymouth. Polyrhabdina spionis is not the organism described by Kölliker as Gregarina spionis, and should be named Polyrhabdina spionis Mingazzini. We do not consider that the epimerite of Polyrhabdina spionis is intracellular, nor do we believe that it is an amoeboid and food-absorbing structure. The specimens we have found in Scolelepis fuliginosa differ in other details from those described by Caullery and Mesnil in the same worm from another locality, and may constitute a new variety. The dicystid gregarine from the intestine of Polydora flava is described by us. This may be the organism called by Caullery and Mesnil Polyrhabdina polydorae, but we do not agree that this name is synonymous with Doliocystis polydorae Léger. We describe two new dicystid gregarines from the intestines of the echiurid worm Thalassema neptuni Gartner at Plymouth. These we have named Hentschelia thalassemae n.gen., n.sp., and Lecythion thalassemae n.gen., n.sp. Association was frequently observed in the gregarines from Thalassema. The gametocytes do not normally develop further until they have been passed out with the excrement. In sea-water a cyst is formed and spores developed. Anisogamy, with flagellated male gametes, has been observed. The dicystid gregarines are a heterogeneous group. Those with simple, transitory epimerite may be related to the acephalines; but the species dealt with in this paper are almost as complicated in structure as tricystids, and seem to differ from these only in the absence of a septum dividing a protomeritic from a deutomeritic segment.
Mechanisms for the Prevention of Self-Fertilization in some Species of Fresh-Water Triclads
Authors: Ullyott P. , Beauchamp R. S. A. 
Published: April 2021

ABSTRACT
Experiments by Gelei (1924) show that some very effective mechanism for the prevention of self-fertilization does exist in Dendrocoelum lacteum. When kept alone from the time of hatching, this species produced cocoons containing eggs which had not been fertilized. Two such animals which had both produced unfertile eggs while isolated, after pairing laid cocoons containing fertile eggs.