bluuebunny/crossref_metadata_2025_split huggingface dataset:
The photographic development of coloured grains in radioautographs
Authors: Sims R. T. , Graham C. A. 
Published: April 2021

ABSTRACT
Tissue sections are prepared and coated with NTB 3 Eastman Kodak emulsion for radioautography in the usual way. After they have been exposed for a suitable time they are processed with no agitation in the following solutions, which must be freshly prepared. Place for 3 min at 24° C in a developer solution which contains per litre 40 g sodium carbonate, 2 g sodium sulphite, 1 g potassium bromide, 2·5 g ‘genochrome’, 40 ml ethylene glycol, and 100 ml acetone in which 2 g of α-naphthol is dissolved. Wash for 2 min in running tap-water. Place for 2 min in a solution containing 30 g potassium ferricyanide and 15 g potassium bromide per litre. Wash for 2 min in running tap-water. Place for 2 min in a solution containing 40 g sodium sulphite, 240 g sodium thiosulphate, and 100 ml commercial formalin per litre. Wash in running tap-water for 2 min. Place in 0· 02% neutral red for 5 min. Wash in distilled water for 1 min. Dip in a solution containing 10 g gelatin and 1 g chromealum per litre, which has been heated in a water-bath until liquid, and then allowed to cool to room temperature. Stand each slide vertically to dry in air, then mount a coverslip with Canada balsam. This method gives blue grains : if red ones are required substitute p-nitrophenylacetonitrile (Eastman Kodak) for α-naphthol.
Further uses and methods of processing of fresh frozen sections of peripheral nerve
Authors: Williams P. L. , Wendell-Smith C. P. , Finch A. , Stevens G. 
Published: April 2021

ABSTRACT
Advantageous modifications of a fresh frozen sectioning technique for peripheral nerve (Williams, 1959) include reduction in size of the block of supporting tissue, the use of human hair as a ligature, the multiple embedding of specimens and the use of liver sandwiches for irregular specimens. Observation with oblique incident illumination indicates that fresh sectioned fibres remain approximately cylindrical. Fresh sections treated for 5 min with common fixatives such as 10% formal saline, Bouin’s fluid, and Flemming’s fluid show widespread changes in the outline, texture, and dimensions of the myelin sheaths. A modified Flemming fixation/haematoxylin staining method may be used with fresh sections; this gives reasonable preservation of the external sheath boundary but is unsuitable for measurements of internal diameter. Luft’s buffered potassium permanganate solution provides an easily standardized, effective method of producing permanent preparations for quantitative studies. Holmes’s silver impregnation technique may be adapted for use with fresh frozen sections. Interferometric estimations may be made upon axoplasm using 5 μ fresh frozen sections in saline. Care must be taken to determine the axoplasmic thickness present. Adequate sampling of an extended section, when using shearing system objectives, may be accomplished by serial stripping of the section under the dissecting microscope.
Ultrastructural differentiation of the basement membrane of the mouse seminiferous tubule
Authors: Baillie A. H. 
Published: April 2021

ABSTRACT
The development of the basement membrane of the mouse seminiferous tubule has been studied between birth and the end of the tenth week of postnatal life by means of the electron microscope. The sheath cells which surround the seminiferous tubules are derived from mesenchymal cells, and differentiation of these specialized cells continues for 5 weeks after birth. Between the plasma membranes of the sheath cells and those of the Sertoli cells there are 3 distinct zones. The zone of decreased electron density nearest the seminiferous tubule is thought to be specialized extracellular fluid filtered by the second or intermediate zone, which consists of numerous fine particles, and the term ‘pseudomembrane’ is advanced for this zone. Collagen develops in the broad outer zone next to the sheath cells and fulfils the support requirements of the growing tubule.
Further information concerning the envelopes surrounding dipteran eggs
Authors: King R. C. 
Published: April 2021

ABSTRACT
A centripetal migration of follicle cells, which results in a separation of egg and nurse chambers, occurs in higher dipterans like Drosophila melanogaster but not in lower dipterans like Anopheles maculipennis. In Anopheles and Drosophila, while the vitelline membrane can be secreted in the absence of the oocyte, the follicle cells must be present. This suggests that the follicle cell is the governing agent in the synthesis of the vitelline membrane. The envelopes of Drosophila embryos differ from those surrounding ovarian eggs in that a membrane about 0 · 04 μ thick lies directly outside the vitelline membrane. This thin layer is thought to represent a waterproofing wax which forms once the egg leaves the ovariole.
Spittle-production and tube-building by cercopoid nymphs (Homoptera). I. The cytology of the Malpighian tubules of spittle-bug nymphs
Authors: Marshall A. T. 
Published: April 2021

ABSTRACT
Use of the basic dyes toluidine blue and alcian blue reveals stacked circular granules, 1 to 3 μ in diameter, and a highly vacuolated material within the cells of the proximal segments of the nymphal Malpighian tubules.
It is suggested that cyclical secretory activity occurs, involving coalescence of the granules and vacuolation, to produce a secretion which is liberated into the tubule lumen and then passes into the hindgut.
The cuticle of Peripatopsis moseleyi
Authors: Robson Elaine A. 
Published: April 2021

ABSTRACT
The integument of Peripatopsis moseleyi has been examined by light and electron microscopy with particular reference to the structure and formation of the cuticle. The evidence supports the idea that Peripatus is a true arthropod but not that it has direct affinities with the annelids. The characteristics of arthropod cuticle are present in their simplest form and pore canals and dermal glands are lacking. The cuticle is 1 or 2µ thick except in the hardened claws and spines. Above the procuticle (chitinprotein) is a thin 4-layered epicuticle. It is possible that the innermost of the 4 layers (prosclerotin) may correspond to cuticulin of other arthropods. In the claws and spines tanning in this layer extends to the procuticle. Hydrofuge properties of the cuticle probably depend on the outer layers of epicuticle, and it is suggested that the lamina concerned might consist of oriented lipid associated with lipoprotein (Dr. J. W. L. Beament). Wax and cement are absent. Non-wettability of the cuticle is probably ensured by the contours of micropapillae which cover the surface. Similar structures arise in Collembola and other terrestrial arthropods by convergence.
The formation of new cuticle before ecdysis is described. After the epicuticular layers are complete, the bulk of the procuticle is laid down in a manner probably common to all arthropods. Secreted materials originate in small vesicles derived from rough endoplasmic reticulum and from scattered Golgi regions. The latter contribute to larger vacuoles which rise to the surface of the cell and liberate material in a fluid state. This later consolidates to form procuticle. Vesicles may also open to the surface directly, and ribosomes probably occur free in the cytoplasm. At this stage the cell surface is reticulate, especially under micropapillae.
The ordinary epidermis has only one kind of cell, attached to the cuticle by tonofibrils disposed like the ribs of a shuttlecock, and to the fibrous sheaths of underlying muscle-fibres by special fibres of connective tissue. These features and the presence of numerous sensory papillae are associated with the characteristic mobility of the body wall. The appearance of epidermal pigment granules, mitochondria, the nuclear membrane, and a centriole are noted. No other cells immediately concerned in the formation of cuticle have been found. By contrast myriapods, which do not have wax either, possess dermal glands secreting far more lipid than is found in the Onychophora. The wax layer found in insects and some arachnids constitutes an advance of high selective value which emphasizes the primitive condition of the Onychophora. It is noted that the thick layer of collagen separating the haemocoel from the epidermis probably restricts the transfer of materials. It is suggested that since some features of cuticular structure and formation appear to be common to all arthropods, it is possible that some of the endocrine mechanisms associated with ecdysis may also be similar throughout the phylum.
The structure of the unpaired ventral nerves in the blowfly larva
Authors: Osborne M. P. 
Published: April 2021

ABSTRACT
The anatomy and histology of the unpaired ventral nerves are described from light- and electron-microscopical studies. Seven unpaired nerves arise from the median dorsal surface of the ventral ganglionic nerve-mass, and terminate in abdominal seg- ments 2 to 8 respectively. Each unpaired nerve bifurcates, sending a lateral nerve to both sides of its respective segment. Subsequently the lateral nerve gives rise to 2 nerve-branches. The first branch runs to a multipolar neurone that is associated with the tracheal system, and the second branch passes beneath the ventral longitudinal muscles and terminates on a ventral transverse muscle. Structurally, the unpaired nerve consists of axons ensheathed by Schwann-cells, the cytoplasmic processes of 2 giant Schwann-cells forming the entire neurilemma sheath of the nerve and its branches. A basement membrane, or connective-tissue sheath, about 2 p. thick surrounds the Schwann-cells. Four nerve-fibres are found in the unpaired nerve; 2 of these bifurcate, sending a fibre into both lateral nerves, but the other 2 fibres pass without dividing, into the left and right lateral nerves respectively, making a total of 2 fibres in both lateral nerves. One fibre from the lateral nerve enters the nerve- branch leading to the multipolar neurone associated with the tracheal system, and eventually joins its cell-body. This fibre is the axon of the neurone. The remaining 2 fibres in the lateral nerve pass into the nerve-branch that runs to the ventral trans- verse muscle. A comparison is made between the unpaired nerves of the blowfly larva and those in other insects.
Semper’s organ, a cephalic gland in certain gastropods
Authors: Lane Nancy J. 
Published: April 2021

ABSTRACT
Semper’s organ has been studied and compared in two genera, Limax and Helix. In both cases the organ, which lies on each side of, and beneath, the buccal mass, is composed of glandular elements surrounding ganglia; the latter originate from two nerves arising from each side of the cerebral ganglia. In both, the organ produces the external swellings that form the mouth lobes on each side of the head. The chief difference between the two is that Semper’s organ is much larger in Limax. In Helix it is reduced to strands of secretory and nervous tissue, dispersed among abundant muscle-fibres.
In H. aspersa the glandular area surrounding the ganglionic part of the organ is composed of three cell-types. The cytoplasm of the chief cellular component, ‘Semper’s’ cells, contains a number of lipochondria, some of which possess the cortex of concentric lamellae typical of phospholipid globules. The cytoplasm of the second cell-type, or ‘mucus’ cell, is filled with electron-lucent globules between which are scattered electron-dense bodies that contain some polysaccharide and lipid. The third cell-type, the reticulate cell, is rather similar to the mucus cell, except that its cytoplasm contains a reticulum formed by strands which lie within, or applied to, the electronlucent globules; these cells contain acid mucopolysaccharides. The structure of the mucus and reticulate cells bears certain resemblances to secretory cells in the sheath of the optic tentacles in the same species.
The function of Semper’s organ is discussed. Certain evidence suggests that some of its secretory cells may have an endocrine activity, and the significance of lipochondria in such actively secreting invertebrate cells is considered.
Serial sectioning of refractory locust eggs
Authors: Anderson D. S. 
Published: April 2021

ABSTRACT
A technique is described for sectioning the yolky tissue of locust eggs. It is a modified version of a method evolved by Griffiths and Carter and successfully used on reptile eggs. The fixative is dioxan saturated with picric acid, with 5% formic acid and 10% formaldehyde. It rapidly penetrates the yolk and minimizes hardening. Dehydration in cellosolve is followed by clearing in benzene. After embedding in wax the block is immersed in 5% tergitol ethane-diol solution, and 12 h later good serial sections are obtained.
Spittle-production and tube-building by cercopoid nymphs (Homoptera). 2. The cytology and function of the granule zone of the Malpighian tubules of tube-building nymphs
Authors: Marshall A. T. 
Published: April 2021

ABSTRACT
The proximal segment of the nymphal Malpighian tubules of tube-building cercopoids consists of two secretory zones, an anterior fibril zone and a posterior granule zone. Cytological changes in the latter are correlated with the production of spittle before each ecdysis. Granules are present in the cells during inter-ecdysal periods. Shortly before spittle-production and ecdysis, coalescence of the granules occurs, followed by cytoplasmic vacuolation and the subsequent liberation of coalesced material into the tubule lumen.
The granule zone is essentially similar to the whole of the proximal segment of the Malpighian tubules of spittle-bug nymphs, although much smaller in length and cross-section. This is consistent with the reduced spittle-producing requirements of tube-building nymphs.
The Cytoplasmic Components of Germ-cells during Spermatogenesis in the Domestic Fowl
Authors: Zlotnik I. 
Published: April 2021

ABSTRACT
1. The Golgi material of the maje germ-cells of the domestic fowl is in the form of a localized body, composed of rods and granules which lie on the surface of the archoplasm.
2. During the maturation divisions the localized Golgi material breaks down and forms a number of granules and rods which become dispersed at the beginning of the metaphase. After each division the scattered Golgi elements reassemble in the daughter cells and become once more attached to the archoplasm.
3. After the formation of the acrosome the Golgi material migrates to the residual cytoplasm and, as the Golgi remnant, is eliminated.
4. Accessory bodies are present in the cytoplasm of the spermatocytes from both silver and chrom-osmium preparations; in the spermatids only argentophil bodies are identified. One argentophil accessory body ‘Golgi X’ is included in the neck region of the spermatozoon.
5. The acrosome is formed from the proacrosome; the latter originates within the archoplasmic vacuole inside the Golgi material of the spermatid. The acrosome occupies the anterior tip of the head of the spermatozoon, and is conical in shape.
6. The nuclear ring is present in the early stages of the metamorphosis of the spermatid ; with the elongation of the nucleus it disappears.
7. The mitochondria are described during all the stages of spermatogenesis ; their ultimate fate is the formation of the mitochondrial sheath of the middlepiece. This sheath often appears in the form of a spiral structure.
8. During the transformation of the nucleus a coiled stage is constant ; this is due to the continuous elongation of the nucleus and lack of response from the cytoplasm. The head of the spermatozoon is an elongate worm-like structure.
9. Two centrioles are present in the spermatids of the domestic fowl. The axial filament originates from the two centrioles. The proximal centriole is attached to the posterior end of the head of the spermatozoon, while the distal centriole assumes the shape of a ring and marks the distal limit of the middlepiece.
10. A clear zone surrounds the posterior part of the nucleus of the late spermatid ; this zone possibly takes part in the formation of the middle-piece.
On the Functional Morphology of the Alimentary Tract of Some Fish in Relation to Differences in their Feeding Habits: Anatomy and Histology
Authors: Al-Hussaini A. H. 
Published: April 2021

ABSTRACT
The mouth is larger and more protrusible in Gobio and Cyprinus than in Rutilus, features which may be associated with the mud-grubbing, bottomfeeding habits of the two former fish, while the arrangement of the adductor muscles in Rutilus enable it to close its mouth more quickly than they and hence it can rapidly snap up its free-moving prey. The selection of food is largely by taste in Gobio and Cyprinus, and hence both are richly supplied with taste-buds from lips to oesophagus, special concentrations being present on barbs around the mouth. Rutilus, on the other hand, augments taste by sight. Taste-buds are accordingly more restricted in distribution and less abundant where they do occur. They are fewer on the lips ; there are no barbs. The relative development of the pharyngeal masticatory apparatus (horny pad, pharyngeal teeth) bears a direct relationship to the amount of plant food in the diet, i.e. it increases in the order Gobio, Rutilus, Cyprinus. The mucus-secreting cells attain their maximum development in the pharynx in all three fishes, as is usual amongst teleosts (cf. Al-Hussaini, 1947a, p. 278) and are thus effectively placed to lubricate the food, irrespective of its nature, at the very commencement of its journey through the gut. Gill-rakers carrying taste-buds and mucus-secreting glands are present in all three fish, but they are exceptionally short in Gobio for a bottom-feeding fish. This may be compensated for to some extent by a pair of food-selecting palatal cushions. All three fishes are stomachless, the short oesophagus joining the pharynx directly to the pyloric sphincter. The loss of the food-holding capacity of the stomach is compensated for by the swelling of the first limb of the intestine. The intestinal tube is longest and its looping most complex in Cyprinus, and shortest and with the simplest looping in Gobio. Four parts are recognized in the intestinal tube, not by external features, but by their mucosal foldings and certain histological characters. An estimation of the mucosal area shows that the absorptive area of the intestinal epithelium is practically equal in the three species when related to the weight of the fish. This ratio has here been called the ‘mucosal coefficient’. The intestinal epithelium comprises two principal histological cell types, viz. the absorptive cell and the goblet cell. The internal surface across which food substances pass from the cells to the tissue fluids is greater in Cyprinus and Rutilus than in Gobio, owing to the greater length of the absorptive cells. In order to be valid, estimations of the relative efficiency of the fish intestine should take into account the relative length of the gut (R.L.G.), the mucosal coefficient (Q.M.), and the length of the absorptive cells.
A Description of a new Zooplankton Counter
Authors: Ward James 
Published: April 2021

ABSTRACT
The new plankton-counting cell is an annular groove machined in a circular plate of lucite. The plate is mounted on a turntable and driven at a rate of about one revolution in six minutes. Counting is done by observation of the rotating sample as it moves through the field of a microscope. This apparatus provides the convenience of the ‘trough and flow systems currently used and has the advantage of being a more compact unit.
Adaptation to rock boring in botula and lithophaga (lamellibranchia, mytilidae) with a discussion on the evolution of this habit
Authors: Yonge C. M. 
Published: April 2021

ABSTRACT
All species of Botula and of Lithophaga live within borings they excavate in rock, In Botula boring is mechanical, into soft non-calcareous rocks. Firm attachment is made by byssal threads arranged in a large anterior and a small posterior group. The rock is abraded by the dorsal surfaces of the valves, which are deeply eroded ; the forces responsible are contraction of the byssal and pedal retractors and the powerful opening thrust of the long ligament. There is no rotation within the boring. In Lithophaga boring is confined to calcareous rocks, byssal attachment being weak and the valves little eroded. The fused inner lobes of the mantle edges may protrude from between the valves anteriorly. They are applied to the head of the boring and it is postulated that they secrete an acid mucus. Some species of Lithophaga bore straight into rock, others rotate in the boring.
Aggregations of foreign particles on the valves of Botula and Lithophaga are due to the effect of accumulations of mucous glands both anterior and posterior to the ligament. The origin and function of these glandular masses is discussed by reference to conditions in the allied Modiolus. They help in disposing of sediment. In Lithophaga the anterior glands, at least, probably secrete an acid mucus. Crystalline calcareous secretions which adventitiously lengthen the shells of certain species of Lithophaga are produced by the walls of the siphons, which may also lay down a calcareous lining to the boring.
Evolution of the boring habit in the Mytilidae is discussed in relation to shell-form. The elongate shell of the dimyarian types Botula and Lithophaga is compared with those of Ensis or Tagelus and shown to be derived from that of a heteromyarian ancestor not unlike Modiolus. The effect of the tangential component in the growth of the mantle/shell counteracts that of reduction of the anterior end of the body and of the mantle/shell associated with heteromyarianism and is also concerned with lengthening of the ligament. Change in form in the Mytilidae made possible change in habit.
The Nervous System of the Ephyra Larva of Aurellia aurita
Authors: Horridge Adrian 
Published: April 2021

ABSTRACT
The rapid co-ordination of the beat had been identified with a specialized system of neurones which spreads over the muscles from the marginal ganglia. By analogy with other invertebrates this has been called the giant fibre system.
The feeding response and the spasm are co-ordinated by a separate net, called ‘the diffuse nerve-net’, which is both physiologically and histologically distinct from the giant fibre system.
The histological structures of the two nerve-nets and the marginal ganglia are described.
Although the diffuse nerve-net contains sensory cells, it also acts upon the muscles, and a double motor innervation is indicated.
The two nerve-nets meet and interact at the marginal ganglia. An attempt has been made to interpret the neurone structure of the ganglia.
Cone Arrangements in Teleost Retinae
Authors: Lyall A. H. 
Published: April 2021

ABSTRACT
There are four types of cone elements in teleosts : single, double, triple, and quadruple cones. The latter two types have only been found as typical elements in minnow (Phoxinus laevis) retinae. The constituent parts of a multiple cone may differ from each other in staining properties and size. A regular arrangement of single and double cones is a feature of many teleost retinae, but these cone patterns are only associated with equal double cones. Changes in the cone patterns occur during growth of the retinae. In trout (Salmo trutta) the pattern in young eyes has many more single cones than that in adult retinae. The loss of these single cones is probably due to their transmutation into rods. The derivation of the typical cone arrangement in central regions of the retina from that found at the periphery has been studied in trout, minnow, and pike (Esox lucius). In all these species there is a similar basic cone pattern at the edge of the retina, although the arrangements in more central parts are very different. It appears that the triple and quadruple cones in minnow retinae are formed by the fusion of a single cone with a double cone and a triple cone respectively.