bluuebunny/crossref_metadata_2025_split huggingface dataset:
On the Intracellular Micro-organisms of some Bostrychid Beetles
Authors: Mansour K. 
Published: April 2021

ABSTRACT
Bhizopertha dominica, F., Sinoxylon ceratoniae, L., and Bostrychoplites Zickeli, Mars., possess paired mycetomes full of bacteria-like micro-organisms. The transmission of the micro-organisms from one generation of the host to the next is carried out in the following way: Micro-organisms from the mycetomes invade the testis lobes, multiply, and mix with the sperms. These micro-organisms pass with the sperms during copulation into the bursa copulatrix of the female. From this region they pass through the micropyle of the fully formed eggs during their passage to the outside, and thus the infection is accomplished. The invasion of the testis lobes by micro-organisms causes abnormality in the process of spermatogenesis. The micro-organisms in the developing egg are first seen near the micropylar region in the peripheral protoplasm. In a later stage these micro-organisms, which have multiplied greatly by then, are to be found in between the yolk globules towards the posterior pole of the egg. From this stage onwards the course these micro-organisms follow till they reach their final destination in the larva has not been followed. The mycetomes throughout life remain quite isolated from the alimentary tract. The biological relation between the micro-organisms and their host is also discussed.
On the Ptilinum of the Blow-fly (Calliphora erythrocephala)
Authors: Laing Joyce 
Published: April 2021

ABSTRACT
An account is given of the morphology, development, and changes following emergence of the ptilinum of the blow-fly. The ptilinum in Calliphora erythrocephala develops from the integument of the anterior part of the head. Differentiation from the surrounding integument begins first as a local thickening of the epidermis. The structure of the thickened area is similar to that of an epidermal imaginal bud. At the end of the third day after pupation at 25° C. this epidermal thickening grows inwards and, as its surface increases, its walls become gradually thinner. Rudiments of the ptilinooesophageal muscle are obvious even immediately after eversion of the head; other muscles do not appear until the fourth day after pupation. In the newly emerged fly the ptilinum is continuous with the integument of the frons, genae, and vertex. Two unpaired and one pair of retractor muscles are inserted on the ptilinum; six other muscles appear to be accessory in connexion with pulsation of the head during emergence. By rhythmic expansion and contraction of the ptilinum the puparium is ruptured and emergence of the fly assisted. After final retraction of the ptilinum into the head-cavity, and hardening of the surrounding head integument, no more use is made of the organ. During the adult life of the fly the ptilinal integument is reduced to a layer of spinules. Before two days have elapsed after eclosion practically all the ptilinal and accessory muscles have disappeared. Their disappearance does not appear to be due to phagocytic activity. From histological evidence the cause and mechanism of muscle degeneration cannot be ascertained. A possible method of origin of the ptilinum from a membranous area above the antennae is suggested. Eristalis, without ptilinum, is compared with Calliphora. From the evidence brought forward it is suggested that the Aschiza and Schizophora represent two independent lines of development.
The Histology, Cytology, and Embryology of Sponges
Authors: Webb D. A. 
Published: April 2021

ABSTRACT
The classical investigations which form the foundation of our knowledge of the minute structure of sponges were mainly carried out in the latter half of the nineteenth century by Haeckel, Schulze, Sollas, Poléjaeff, Topsent, Minchin, Maas, and other workers. In the earlier years of this century while many papers were published dealing with taxonomy, skeletal structure, physiology and descriptions of new species, the study of the soft parts was somewhat neglected, though the work of Minchin forms an important exception. More recently, however, a revival of interest in these aspects, assisted by modern fixing and staining methods, has resulted in a considerable increase in our knowledge. It is the aim of this paper to give a résumé of the literature published during the last twenty year which deals with those aspects of sponges indicated in the title. 1914 has been chosen as the beginning of the period since all previous references are available in Vosmaer’s bibliography.1
On the Ciliary Mechanisms and Interrelationships of Lamellibranchs: PART I: New Observations on Sorting Mechanisms
Authors: Atkins Daphne 
Published: April 2021

ABSTRACT
The gills of Solen marginatus, Ensis siliqua, and Ensis arcuatus are synaptorhabdic or eulamellibranchiate, and the lamellae plicate and heterorhabdic. The latero-frontal cilia are large; there are in addition small subsidiary laterofrontal cilia. The frontal cilia on the filaments forming the bottom of the plical grooves are fine and beat dorsally. In the two species of Ensis the frontal cilia on the filaments forming the sides and apices of the plicae are arranged in two tracts with the effective beat in opposite directions; in Solen marginatus in three tracts, a median one of coarse cilia beating ventrally and two outer ones of fine cilia continuously beating dorsally.
In both genera the movement of particles in the plical grooves is dorsalward; on the crests mainly ventralward; on the sides of the plicae ventral or dorsal according apparently to their type and number.
Along the marginal grooves of the demibranchs, between the bases of the two demibranchs of a gill, and along the dorsal edges of all the ascending lamellae, currents are towards the mouth.
The gills of Cultellus pellucidus are synaptorhabdic or eulamelhbranchiate, and the lamellae flat and homorhabdic. The ventral edge of the outer demibranch is ungrooved. On the frontal surfaces of the filaments of both lamellae of the inner and the ascending lamella of the outer demibranch there are, in addition to fine cilia, a tract of long, coarse ones which beat ventrally. The fine frontal cilia, which alone are present on the descending lamella of the outer demibranch, beat dorsally, and, so far as could be ascertained, the tracts of fine cilia on the other three lamellae of the gill also beat dorsally.
The obvious frontal currents are toward the ventral edge on both lamellae of the inner and on the ascending lamella of the outer demibranch, and dorsalward on the descending lamella of the outer demibranch. Along the marginal groove of the inner demibranch, between the bases of the two demibranchs of a gill, and along the dorsal edges of all the ascending lamellae, currents are towards the mouth.
The Cytology of Amoeba proteus ‘Y’ and the effects of large and small Centrifugal Forces
Authors: Singh B. N. 
Published: April 2021

ABSTRACT
When Amoebaproteusis subjected to high centrifugal force most of the cytoplasmic bodies are thrown out of the cell, so this work was done with the ordinary electrical centrifuge. The stratification of the various cytoplasmic components according to their specific gravity is as follows: the contractile vacuole and the fat, being the lightest, occupy the centripetal position; then there is a layer of cytoplasm followed by mitochondria, neutral-red bodies, crystals, and nutritive spheres. The nucleus occupies a position in between the crystals and the nutritive spheres (Text-fig. 2). The redistribution of the various cytoplasmic components takes place within a few minutes after amoebae have been centrifuged by the electrical centrifuge. Ultra-centrifuged organisms kept in culture solution remain rounded for 10-15 days, and no cyst formation takes place. The crystals and nutritive spheres are reformed; the former seem to be the products of excretion formed by the metabolic activity of the cell. The nutritive spheres contain glycogen as reserve food material, and give positive tests for glycogen with iodine and Best’s carmine. There is no evidence that the bodies which stain with neutral red are the homologue of the metazoan Golgi apparatus, although they are pre-existing bodies in Amoeba proteus. The contractile vacuole does not blacken even after prolonged osmication. No certain homologue of the Golgi apparatus was found in Amoeba proteus. Fat and glycogen are two distinct types of storage material present in Amoeba proteus. The former is very well seen with osmic acid, Sudan IV, and Nile blue tests.
A Study of the Mitochondria of Trypanosomes
Authors: Wotton Robert M. 
Published: April 2021

ABSTRACT
Early observers noted the presence of grannies of indeterminate character in the cytoplasm of certain species of trypano-somes (Franca, 1907 : Policard, 1910). Efforts to establish the nature of these granules by the use of vital stains were not especially fruitful, although the general opinion was held from the beginning that they were not degeneration products of the cell. Shipley (1916), after a careful and thorough study of these cytoplasmic elements in one species of trypanosome, Trypanosoma lewisi, supravitally stained with J anus green, and with fixed preparations, concluded that they were mitochondria. Although their nature is still somewhat uncertain, it seems best to accept this hypothesis. In the present paper the results of the study of several species of trypanosomes are reported with respect to the possible presence of mitochondria. Some of the species of parasites have come directly from experimental vertebrate hosts, one has come from the arthropod vector, and another from culture. Since the mitochondria of the cells of higher species of animals have been associated with certain metabolic functions, the possibility of a relationship between the mitochondria of trypanosomes and trypanosome physiology has been kept in mind while the present study was being carried on.
The Reproductive System and associated organs of the Brittle-star Ophiothrix fragilis.
Authors: Smith J. E. 
Published: April 2021

ABSTRACT
The organs associated, either directly or indirectly, with reproduction in the Ophiuroidea are the axial organ and related sinuses (axial organ complex), the genital rachis, the gonads (localized expansions of the rachis), the gonoducts, and the genital bursae. Evidence is presented in favour of the view of Fedotov (1924) that the axial organ of Ophiuroids is made up of two closely associated parts each surrounded by its own sinus from the wall of which it is, during development, proliferated. The left axial sinus (aboral in the adult) is derived from the left anterior coelom of the larva, the right axial sinus (oral in the adult) from the madreporie vesicle which itself is a derivative of the right anterior coelom of the larva. The ampulla of the stone canal is continuous with, and is part of, the left axial sinus. An account is given of the morphology and histology of the genital rachis and sinus. Examination of the gonads of female Ophiothrix indicate that the breeding season extends from about March to October and that, during this time, there is periodic emission of ova, probably at monthly intervals. Males, on the other hand, produce sperm all the year round. The genital bursae number two pairs to each interradial pouch. They serve, primarily, as organs of respiration. Special mechanisms, which are described, are concerned in the intake and expulsion of water. The gonads do not discharge their products directly into the genital bursae nor through temporarily formed pores in the body-wall but through specially developed and permanent gonoducts, one to each of the ten gonads. Young specimens found in the genital bursae have attained their position only after a period of free-swimming larval life. After settling and metamorphosing, some of the young individuals crawl into the bursae. As a consequence of the previous observation it is pointed out that the presence of the young within the genital bursae of the adult is by no means an indication of a viviparous habit.
The Fate of Spermatozoa in the Female Dogfish (Scylliorhynus canicula)
Authors: Metten H. 
Published: April 2021

ABSTRACT
1. References are given to the literature concerning the fate, in various vertebrates, of spermatozoa in the female genital tract.
2. In the dogfish, penetration of the oviducal wall by spermatozoa does occur. It is confined to the ‘uterus’ and about five millimetres of the oviduct anterior to it. The latter suffers a denser invasion than the ‘uterus’. No spermatozoa invade the cloacal epithelium.
3. Epithelial vacuoles are found in the ‘uterus’, where they may or may not contain spermatozoa, and in the cloaca, where they do not. Any of the vacuoles may contain red and white blood corpuscles.
4. Vacuoles containing blood corpuscles account for a continuous ‘uterine’ bleeding on a small scale.
5. Desquamation of the ‘uterine’ epithelium is slow and continuous, that of the cloacal epithelium intermittent and heavy. Desquamation is not related to the time of copulation.
6. Digestion of spermatozoa and blood corpuscles within the vacuoles may be very incomplete.
7. The spermatozoa which enter the columnar epithelium near the ‘uterus’, frequently pass right through and into the superficial connective tissue. No vacuoles are produced in the columnar epithelium. Presumably all such spermatozoa are phagocytosed.
8. No fusion occurs between the heads of the spermatozoa and thé nuclei of any of the cells of the oviducal wall, as described by Kohlbrugge.
9. The proportion of spermatozoa destroyed in the lower oviduct is not sufficient to prevent them ascending the upper oviduct in large numbers.
10. A theory is advanced to account for the facts concerning the destruction of spermatozoa in the oviduct.
Some Histochemical Observations on Amino-acids and Nucleic Acids in the Wool Follicle
Authors: Ryder M. L. 
Published: April 2021

ABSTRACT
A study of staining at different pH values showed that the fibre became decreasingly basiphil at successively higher levels. This was supported by an increased reaction for basic groups after keratinization, although a reaction for acid groups was obtained in the normally basiphil pre-keratinization region, and the keratinized fibre after vigorous treatment.
The reactions for individual amino-acid residues are probably not quantitative, but indicate availability to react. The strongest reaction for arginine was in the tricho- hyalin of the medulla and inner sheath, for tyrosine and tryptophan in the keratinized part of the fibre, and for histidine in both the keratinized and unkeratinized parts.
Most reactions gave asymmetrical results, but vigorous treatment tended to produce uniform results. This supports the suggestion that the asymmetry is due to differences in accessibility rather than to chemical differences.
An Electron Microscope Study of a Small Free-living Amoeba (Hartmanella astronyxis)
Authors: Deutsch K. , Swann M. M. 
Published: April 2021

ABSTRACT
The fine structure of a species of small free-living amoeba, Hartmanella astronyxis, has been investigated. The mitochondria resemble those of other species of amoeba. Structureless bodies of about the same size as mitochondria are sometimes found in association with them. Double membranes are common in the cytoplasm, and may show granules along their outer borders. The nuclear membrane is a double-layered structure, with a honeycomb structure evident in tangential sections. The cell membrane is also double-layered, or occasionally multi-layered.
A Quantitative Study of the Cytoplasm of Ascites Tumour Cells in Mice
Authors: King R. J. 
Published: April 2021

ABSTRACT
This paper describes how a combination of microspectroscopy and interference microscopy has been used to investigate the composition of the cytoplasm of fresh ascites tumour cells of mice. The accuracy of the microspectroscopic method will be very dependent on the standard absorption curves used (i.e. results obtained from dilute nucleic acid and protein solutions of known concentration), and particular attention has therefore been given to this aspect of the investigation. Thus, the standard protein absorption curve has been derived in two ways, first from a certain assumed amino-acid composition, and secondly by a method involving the optical density and refractive index of the ascitic fluid itself. Both methods are shown to result in similar cellular analyses.
The cytoplasm of the ascites cell can be divided broadly into two regions—a granular zone of comparatively low ultra-violet absorption, and a peripheral region possessing greater absorption, but with little structure visible by the optical microscope. Absorption measurements at 257 and 275 mμ show that, despite the difference in ribonucleic acid content in these two regions, the protein concentrations are approximately the same.
For comparison with these microspectroscopic results, optical retardations have been measured in the identical regions of the same ascites cells. Total dry mass concentrations, evaluated interferometrically, were found to be in good agreement with the sum of the nucleic acid and protein weights, these being obtained from the ultraviolet results. This indicates that the ultra-violet absorption of the cytoplasm of the fresh ascites cell is not grossly different from that to be expected from its extracted nucleic acid and protein components. It is stressed that the material used in this investigation was in many ways suitable for quantitative absorption measurements and equally consistent results should not be expected from all other types of cells, particularly those measured after fixation rather than in a fresh condition.
Observations upon the Nervous Systems of Pelagic Tunicates
Authors: Bone Quentin 
Published: April 2021

ABSTRACT
The sensory and motor systems of the pelagic tunicates Doliolum, Salpa, and Thalia are described, chiefly from observations made upon the living animals by phase-contrast microscopy. These observations confirm and extend previous work, showing that the sensory systems of these animals are anatomically highly specialized. Details of the sensory cells are shown from living specimens. It is shown that the motor systems of Doliolum and the salps are essentially similar, but that of Doliolum is less specialized. The condition of the visceral nervous system in these animals is discussed, and it is concluded that the salps possess peripheral nerve-cells upon the viscera; illustrations are given of these cells from fixed specimens.
The Use of the Philips ‘Mirror-condenser Lamp’in Microscopy
Authors: Baker John R. , Llowarch Wilfrid 
Published: April 2021

ABSTRACT
The primary source of light is a coiled filament. Ellipsoidal and spherical mirrors collect nearly all the light it produces and project it on to an area of about mm outside the bulb. One end of a solid glass rod is placed in or near this area. The light travels along the rod by internal reflexions. A bull’s-eye lens, placed beyond the other end of the glass rod, focuses the emerging light on the lower focal plane of the substage condenser of the microscope. Very intense illumination is produced. It is moderated by a variable resistor.
The lamp is suitable for use with objectives of focal lengths from 16 mm downwards. It is particularly adapted to high-power microscopy of all sorts. It is easy to use.
Sections of Fresh Mammalian Nerve-trunks for Quantitative Studies: A Rapid Freezing Technique
Authors: Williams P. L. 
Published: April 2021

ABSTRACT
Attempts to assess the effects of shrinkage and distortion inherent in the conventional histological procedures used during quantitative analysis of nerve structure have hitherto proved unsatisfactory. The evolution of a technique in which such effects are minimized is therefore desirable.
A segment of fresh nerve, implanted in a mass of supporting tissue (fresh liver), is frozen by a solid CO2/acetone mixture, and sectioning is subsequently performed in a cryostat. The sections are flattened on pre-cooled slides, irrigated with saline, and photographed.
Regular, stable serial sections, 3 to 5 μ in thickness, may be produced. Such sections show typical internodal annuli of compact myelin, shearing defects of Schmidt-Lanterman type, and paranodal crenations of the myelin sheath. Occasional defects of preparation include rupture of isolated fibres, herniation of myelin, and the appearance of myelin spheres.
When studies involving precise measurement are contemplated, the use of orthodox transmitted illumination, dark-ground illumination, and phase contrast is precluded by diffraction effects and the occurrence of reverse-contrast haloes at the tissue interfaces. Polarizing microscopy has proved satisfactory.
It has been shown that estimates of the relative size of the axon and myelin sheath, obtained from sections prepared in this manner, do not differ significantly from the relative sizes measured in fibres freshly teased in physiological saline (Wendell-Smith and Williams, 1959).
The Association of a Slime Bacterium with the Inner Envelope of the Egg of Dytiscus marginalis (Coleóptera), and the less common Occurrence of a similar Bacterium on the Egg of D. semisulcatus
Authors: Jackson Dorothy J. 
Published: April 2021

ABSTRACT
The egg of Dytiscus marginalis L. is laid under water in the mesophyll of the leaf of various aquatic plants. The egg increases in size during development and this results in the splitting of the chorion, the outer envelope of the egg, usually into two halves. The inner envelope of the egg, the vitelline membrane, then forms the only complete shell of the egg in its later stages.
During the development of the embryo of D. marginalis the cysts of a slime bacterium (myxobacteriale) appear in great numbers on the vitelline membrane along the dorsal surface of the embryo and around each end of the egg. They are at first small and scattered, but by the time the larva hatches they are present in dense colonies.
These bacterial cysts occur on eggs collected from water plants in ponds; but they develop just as readily on eggs obtained in the laboratory by placing the female D. marginalis in jars of tap-water with leaves that have never before been immersed in water.
Slime bacteria in the vegetative stage are carried in great numbers by the female D. marginalis, as has been shown by trailing the apex of the abdomen of a living beetle over an agar culture, when swarms of the characteristic rod-like cells have been obtained. Some of these bacteria will be transferred from the beetle to the egg during oviposition.
The bacterial cysts do not occur on unhealthy eggs and they rarely show normal development on eggs parasitized by the mymarid, Caraphractus cinctus Walker. This suggests that their development is dependent upon the healthy growth of the Dytiscus embryo.
In the egg of D. semisulcatus Mull, the chorion remains in close contact with the vitelline membrane throughout embryonic development and only occasionally shows small irregular cracks before hatching. On some eggs of this species a few scattered cysts of slime bacteria occur on the vitelline membrane. On occasional eggs they were more numerous, but they were never observed to be present in sufficient numbers to form the even covering which is so striking a feature of certain parts of the egg of D. marginalis.