bluuebunny/crossref_metadata_2025_split huggingface dataset:
Studies on Lagenophrys tattersalli sp. n. (Ciliata Peritricha, Vorticellinae). Part I. Structure, Asexual Reproduction and Metamorphosis
Authors: Willis A. G. 
Published: April 2021

ABSTRACT
1. The diagnostic characters of a new marine ciliate, Lagenophrys tattersalli, have been described. The lorica is chiefly distinguished by the possession of a ventral shelf, a clearly defined central cap and a marginal zone formed during metamorphosis. The adoral spiral of about two turns is distinguished by the possession of an undulating membrane.
2. The macronucleus consists of a chromatin network with a plastin component in the form of interspersed spherical plasmosomes.
3. Reserve substances are present at certain stages of the life cycle in the form of spheres composed of mixtures of fats and lipoids (chiefly cholesterol and cholesterol esters). The reserve substances accumulate during the trophic period and reach their maximum abundance prior to division.
4. Asexual reproduction takes place by two types of division leading in each case to the separation of motile organisms or swarmers and non-motile residual organisms.
5. The swarmer is always provided with a considerable quantity of fatty and lipoid reserve material. This is derived by the equal or unequal partition of the reserve material of the parent.
6. The peristome and ciliary girdle of the swarmer are formed from the division of the peristome and adoral spiral, respectively, of the parent and do not arise de novo.
7. It is maintained that the ciliary girdle of L. tattersalli does not correspond to the true ventral cilia of forms like Trichodina.
8. The ciliary girdle of the swarmer is disposed around a cavity (the sucker cavity) which was originally continuous with the vestibule of the parent. The ciliary girdle and the contractile vacuole of the swarmer are associated with the sucker cavity in the same way as the adoral spiral and contractile vacuole of the parent are associated with the vestibule.
9. In metamorphosis the sucker cavity of the swarmer becomes distended, probably by the secretion of fluid. This growth cavity, as it may be termed, increases the superficial area of the protoplasm until the dimensions of the adult lorica are attained. The marginal zone of the lorica is laid down at this period and the growth cavity afterwards decreases in size. The adoral spiral of the adult is formed from the ciliary girdle of the swarmer after the cilia of the latter have become absorbed. The growth cavity is absorbed into the vestibule.
10. The reserve materials of the swarmer are completely used up before the end of metamorphosis.
On the Pituitary of the Perch (Perca fluviatilis).
Authors: Kerr T. 
Published: April 2021

ABSTRACT
1. A general description is given of the pituitary of the perch (Perca fluviatilis L.), and histological details of its various parts. The subdivisions of the glandular component are confluent with each other but distinguished by their different cell types. The nervous lobe makes contact with all three of the subdivisions, but is separated from them by a layer of connective tissue, incomplete in particular areas.
2. The anterior glandular region (anterior lobe) has an anterior chromophil and a posterior chromophobe zone. The middle glandular region (transitional lobe) possesses brightly staining acidophils and basophils as well as chromophobes. The acidophils form a dorsal sheet, deeply indented by processes of the nervous lobe, the basophils lie ventrally and posteriorly, and chromophobes are common towards the extremities of the indentations. The posterior glandular region (intermediate lobe) is elaborately penetrated by nervous lobe processes ; the cells are small and consist of amphiphils, dull basophils, and occasional dull acidophils. The possible homologies of these regions to the lobes of higher types are discussed. The nervous lobe is of loose glial tissue with many nuclei and blood vessels and some reticular and collagenous fibres.
3. Strongly acidophil spheres of various sizes and in various numbers occur in the middle glandular region. They originate in ‘sphere cells’ resembling eosinophil leucocytes and after enlarging become free in the tissues of the region. Later they appear to pass into the posterior processes of the nervous lobe to be the larger bodies of the Herring material. Finally these larger elements appear to break down to form a fine granulation, whose further fate could not be followed.
Amoeba lescherae (nov. spec.)—Its morphology, cytology, and life-history
Authors: Taylor Monica , Hayes Catherine 
Published: April 2021

ABSTRACT
1. The discovery of a new species of large, free-living freshwater amoeba is recorded, and a description of the adult and of its reproduction is given. Although provisionally called Amoeba lescherae, it may have to be placed in the genus Chaos.
2. A method of cultivating it in the laboratory on a diet of small flagellates and ciliates subsisting on a pabulum of wheat grains is detailed. By starting them in Petri dishes pure line cultures are shown to be easily obtainable.
3. The resting nucleus, discoid in shape, has been shown to bear a general resemblance to that of Amoeba discoides as well as Amoeba proteus Y. Division is mitotic, and occurs once in twenty-four hours under optimum conditions. In contrast to Amoeba proteus Y the separation of the daughter amoeba is facilitated by the mechanical support of minute fragments of floating debris.
4. The cytoplasmic contents include square prismatic crystals, nutritive spheres, fat globules, neutral red bodies, and mitochondria.
5. It has been shown that while the adult has a general resemblance to Amoeba proteusY the respective developmental stages of the two amoebae are in marked contrast.
6. Agametogony is seen to begin with the emission of ‘chromidia’ from the nucleus. These chromidia form the rudiments of the agametes which differentiate into cysts. Excystationis described.
7. Agametogony occurs more frequently in Amoeba lescherae than in Amoeba proteus Y, the intervals between the ‘depression’ periods being shorter in the former than in the latter.
8. The development of the nucleus from the newly hatched amoeba to its adult condition has been traced, and the immature nucleus has been contrasted with that of species of M a y o r e l l a.
The Meiotic Phase of Calandra oryzae
Authors: Gunson Mary M. 
Published: April 2021

ABSTRACT
The somatic chromosome number for the female of Calandra oryzae is twelve ; for the male, eleven. The latter is presumably of XO composition. In both sexes the haploid number of loosely paired threads is present at early diplotene. Upon condensation, the ex-conjugant chromosomes undergo a temporary complete dissociation into their univalent constituents, so that the diploid number of separate elements is reconstituted. At the equatorial plate stage the twelve univalent chromosomes associate once again into .six bivalents. In the female this is followed by a precocious separation of the anaphase chromatids, so that by the conclusion of the first meiotic division the diploid number of chromosome elements is evident at both ends of the spindle. There is no comparable process during the course of spermatogenesis; at anaphase I the haploid set of chromosomes passes to each pole, the nuclei so produced entering a resting condition.
On the Origin of the Acrosome and the Be-haviour of the Nebenkern in Diestrammena sp
Authors: Wu Chang-Chun 
Published: April 2021

ABSTRACT
In the early spermatocyte of Diestrammena the Golgi material and the chondriosomes are aggregated on one side of the nucleus. During the growth period both spread out around the nucleus and become evenly scattered through the cytoplasm.
During the maturation divisions the chondriosomes, in the form of threads, surround the mitotic figure as a mantle and are distributed equally to the daughter cells during telophase. During these stages Golgi bodies could not be demonstrated by any of the methods used.
The acrosome is of multiple origin. It is formed separately from the chromophobic material of the Golgi bodies, which never fuse together to form a single acroblast, as is frequently observed in other forms. After the acrosome is complete the Golgi remnants migrate posteriorly and slough off along the tail with the cytoplasmic remnant.
The acrosome sphere migrates to the anterior pole and presses on the nuclear membrane. Within this sphere two portions of chromatic substance are formed; these fuse and elongate to form the front piece of the sperm.
As spermiogenesis goes on, the chromatin within the nucleus forms a peripheral layer inside the nuclear membrane. Finally the nucleus elongates to form the head of the sperm.
The chondriosomes condense to form the Nebenkern. This then differentiates into chromophilicand chromophobic substance. The former appears as a plate embedded in the latter and gradually decreases in amount. At the same time the central substance appears within the chromophobic substance. When the chromophilic substance has completely disappeared,, the Nebenkern divides into two equal parts. It then spins out as two series of blebs. Eventually the blebs disappear and the materials thus left twist around each other to form the sheath of the tail.
On the anterior side of the nucleus there exist some granules. Their origin and nature are doubtful. They resemble the fat droplets in the spermatid of Hemiptera. Ultimately they are sloughed off along the tail together with the cytoplasmic remnant.
Development of Olfactory Organ in Rana nigromaculata
Authors: Tsui Chi-Lan 
Published: April 2021

ABSTRACT
The anlage of the olfactory placode arises from the sensory layer of the ectoderm. There is no oro-nasal groove between the olfactory placode and stomodaeum. The primitive choana opens into the endodermal part of the oral eavity. The lateral appendix is the earliest formed blind sac. It degenerates and disappears at the end of the third stage. There are three blind sacs in the larval stage: the upper, anterior lower, and posterior lower sac. The first and third sacs together become the cavum principale and recessus lateralis, while the second becomes the cavum inferius and recessus medialis in the adult stage. The nasal cavities undergo considerable shrinkage during metamorphosis. Extra blind sacs may be formed in the later larval stage. The naso-lacrymal duct arises in the dorso-lateral part of the cavum principale and extends to the lower eyelid. The process of hollowing out appears to begin from the distal end. There are four kinds of glands in the nasal cavity—medial nasal, lateral nasal, Bowman’s, and pharyngeal gland. The first one arises earlier than the other three.
The Function of Chromatocytes in the Simuliidae, with Notes on their Behaviour at the Pupal-adult Moult
Authors: Hinton H. E. 
Published: April 2021

ABSTRACT
In the larvae and pupae of the Simulidae the cuticle and epidermis of the thorax and abdomen are more or less transparent, and the colour pattern is formed by cells (chromatocytes) that contain pigment granules..These cells always lie below the basement membrane. It is possible to photograph the chromatocytes without damage to the animal and thus to make photographic records of the behaviour of particular chromatocytes over a period of many days when the animal is moving about and feeding in the normal way.
The chromatocytes accumulate lipids. The accumulation of lipids during larval growth and their depletion during adult development has been photographed in normal undamaged animals.
Conspicuous changes in the colour pattern, especially of the thorax, occur at metamorphosis. Such changes are due to mass migrations and the formation of new aggregation patterns by the chromatocytes. While such movements of the chromatocytes are taking place in some parts of the body, the aggregation patterns of chromatocytes in other parts of the body remain unchanged and appear to be unaffected by the events that initiate and accompany moults and ecdyses.
A Study of Rawitz’s ‘Inversion Staining’
Authors: Przełęcka Aleksandra 
Published: April 2021

ABSTRACT
The Rawitz method involves mordanting with tannic acid and potassium antimony tartrate, and staining with basic fuchsine. The mordanting causes basic fuchsine to act as though it were an acid dye (‘inversion staining’).
A modification of the method is described in the present paper. This modification makes it possible to obtain the same results in a shorter time.
The chief substances stained by Rawitz’s method are phospholipids, certain proteins, and certain polysaccharides.
Although the method cannot be regarded as a cytochemical test in the strict sense, yet it gives useful indications of chemical composition and in addition is valuable to the morphological cytologist as a technique for showing certain cytoplasmic inclusions (mitotic spindle, acrosome, mitochondria, ‘Golgi apparatus’ of certain cells).
The Histology of the Nervous System of anInsect Rhodnius prolixus (Hemiptera): I. The Peripheral Nervous System
Authors: Wigglesworth V. B. 
Published: April 2021

ABSTRACT
While studying the osmium/ethyl gallate method of fixation and staining (Wigglesworth, 1957) a number of incidental observations were made on the nervous system of Rhodnius. This staining method reveals particularly those structures most rich in lipids, the cell membranes, fat droplets, mitochondria, and ‘Golgi element’, giving a picture which closely resembles that seen with the electron microscope. This appearance is so different from that shown by standard methods of staining, that it seemed worth while to re-investigate the histology of the nervous system of the insect by its use. That should provide a useful background to the electron microscope studies being made at the present time. In this paper, the first of three which are projected, certain parts of the peripheral nervous system are described.
An Improved Radioautographic Method for demonstrating Tyrosine Uptake and Tyrosinase Activity in Melanocytes
Authors: Brunet P. C. J. , Small P. L. 
Published: April 2021

ABSTRACT
A method for studying the melanogenetic activity of pigment cells is described. Tissue is incubated in a medium containing tyrosine labelled with I4carbon. Tyrosine, being a precursor of melanin, is incorporated into the insoluble pigment. This can be detected in histological selections by radioautography. A measure of tyrosine uptake and, provided precautions are taken, of tyrosinase activity, can be gained by the use of this technique. There are advantages in using labelled, rather than ‘cold’ substrate.
This technique, developed by other workers, has been used with success; but difficulties arise in situations where intense pigmentation obscures the image of the superimposed radioautograph. Here consideration is given to the possible methods for circumventing this difficulty, and a satisfactory method for partially bleaching the pigment, without upsetting the radioautograph, is described in detail.
The Small Leg-nerve of Spiders and a Probable Mechanoreceptor
Authors: Parry D. A. 
Published: April 2021

ABSTRACT
Besides the main leg-nerve there is, in spiders, a ‘small leg-nerve’ which is mainly sensory. About 8 of the fibres arise from neurones which form a ganglion at the femur-patella joint and appear anatomically to be joint mechanoreceptors, but if so must supplement the lyriform organs. Cutting the small leg-nerve has no effect on the walking pattern nor on the detection of prey, which almost certainly depends on mechanoreception. The small leg-nerve contains one motor fibre which innervates the claw elevator. This muscle has a double innervation, a second fibre running in the main leg-nerve. There are interesting parallels between the small leg-nerve in spiders and Limulus.
The Ligament of the Lucinacea (Eulamellibranchia)
Authors: Allen J. A. 
Published: April 2021

ABSTRACT
The basic structure of the opisthodetic ligament of the Lucinacea consists primarily of inner layer, anterior and posterior outer layers, and periostracum. This is secondarily extended by fused periostracum and fusion layer. Fused periostracum extends as far as the posterior adductor muscle and, except in the Ungulinidae, to the anterior adductor. The fusion layer covers the posterior outer layer and a little beyond. Only in Loripes lucinalis is the fusion layer to be found anteriorly. Below the umbos the inner layer, posterior outer layer, and overlying fusion layer are split. This split can be explained in terms of the growth and form of the shell. The anterior outer layer fills the split and extends to the anterior limit of the lunule. The ligament, external in the Ungulinidae, becomes progressively more internal. At the same time the posterior limit of the outer layer becomes modified as a result of the elongation of the outer surface of the outer mantle fold between the pallia! lobes in the depth of the posterior mantle embayment. The Lucinidae are most specialized in this respect where, in L. lucinalis, a tongue of tissue divides much of the ligament horizontally. The Thyasiridae, the remaining family of the group, occupies an intermediate stage in this specialization.
Patterns of Myo-neural Junctions and Cholinesterase Activity in the Muscles of Tadpoles of Xenopus laevis
Authors: Lewis P. R. , Hughes A. F. W. 
Published: April 2021

ABSTRACT
A simultaneous coupling azo dye technique has been used to reveal the distribution of cholinesterase activity in the musculature of the developing tadpole of Xenopus laevis. The use of inhibitors and a less convenient but more specific histochemical technique confirmed that only true cholinesterase distribution was being demonstrated; and a study of silver-impregnated material proved that this azo dye technique provides a very convenient method of following the development of the patterns of myo-neural junctions in the striated muscles of this tadpole. A wide variety of patterns is seen in the various muscles; in the axial musculature the muscle-fibres become innervated at their ends from myocommatal plexuses and never acquire endings along their length; broad muscular sheets, as in the walls of the branchial and abdominal cavities, are also first innervated terminally from the septa but later acquire secondary patterns of innervation over their surfaces; while in long narrow muscles the main innervation is along the lengths of the fibres. These different patterns of innervation are correlated with the functions of the various types of muscle. It is suggested that terminal innervation may be a special adaptation to permit rapid establishment of neurogenic activity, the pattern of endings of the more usual type forming when the need for precisely co-ordinated reflexogenic activity arises. In some muscles, the azo dye technique reveals a profuse multiple innervation of the fibres which are assumed to be of the so-called ‘slow type’ known to exist in some amphibian muscles.
The Structure of the Nervous System in Velella
Authors: Mackie G. O. 
Published: April 2021

ABSTRACT
Silver staining methods have been applied to the nervous system of Velella, Two histologically distinct plexuses are described under the headings ‘open’ and ‘closed’ systems. The open system consists of neurones with fine processes which run for distances of up to 2 mm, retaining their independence ins pite of frequent contacts with other fibres. The fibres of the closed system are large and run together, forming a nerve-net in which neurofibrillar material from different neurones intermingles; it is provisionally to be regarded as a syncytium. A certain type of ‘fibre’ in this system is believed to arise secondarily by the drawing out of adhesion connexions into long strands. Free nerve-endings resembling growing-points occur in both systems. The two systems occur throughout the ectoderm, but in the invaginated ectoderm the open system is poorly developed. The functions of the two systems are not known, but the closed system is probably specialized for through-conduction.
Neuro-sensory cells occur in the external ectoderm, making contact with fibres of both open and closed systems. No specialized endings have been found in a muscular region examined. No nerve-rings or centres have been found. Nerves are sparsely distributed in the endoderm, but they lie independently of one another and of ectodermal nerve-fibres crossing the mesogloea between the invaginated and external ectoderm layers.
The Ligamentary System and the Segmental Musculature of Nephtys
Authors: Clark R. B. , Clark M. E. 
Published: April 2021

ABSTRACT
Nephtys lacks circular body-wall muscles. The chief antagonists of the longitudinal muscles are the dorso-ventral muscles of the intersegmental body-wall. The worm is restrained from widening when either set of muscles contracts by the combined influence of the ligaments, some of the extrinsic parapodial muscles, and possibly, to a limited extent, by the septal muscles. Although the septa are incomplete, they can and do form a barrier to the transmission of coelomic fluid from one segment to the next under certain conditions, particularly during eversion of the proboscis.
Swimming is by undulatory movements of the body but the distal part of the parapodia execute a power-stroke produced chiefly by the contraction of the acicular muscles. It is suspected that the extrinsic parapodial muscles, all of which are inserted in the proximal half of the parapodium, serve to anchor the parapodial wall at the insertion of the acicular muscles and help to provide a rigid point of insertion for them.
Burrowing is a cyclical process involving the violent eversion of the proboscis which makes a cavity in the sand. The worm is prevented from slipping backwards by the grip the widest segments have on the sides of the burrow. The proboscis is retracted and the worm crawls forward into the cavity it has made. The cycle is then repeated.
Nephtys possesses a unique system of elastic ligaments of unusual structure. The anatomy of the system is described. The function of the ligaments appears to be to restrain the body-wall and parapodia from unnecessary and disadvantageous dilatations during changes of body-shape, and to serve as shock-absorbers against the high, transient, fluid pressures in the coelom, which are thought to accompany the impact of the proboscis against the sand when the worm is burrowing. From what is known of its habits, Nephtys is likely to undertake more burrowing than most other polychaetes.