bluuebunny/crossref_metadata_2025 huggingface dataset:
Photoreceptors of Lumbricus terrestris, with special reference to their distribution, structure, and function
Authors: Hess Walter N.
Published: February 2005

A special type of cell, called ‘Lichtzellen’ by Hesse, was found in the photosensitive regions of the earthworm. Wherever the epidermis is most sensitive to light these cells are most abundant. They are found in the epidermis of all segments of the body and also in nerve enlargements of the prostomium and the caudal segment, but the intersegmental and ventral regions of the different segments, except the more distal ones, contain none of them. They are supplied by nerves and each contains a characteristic inner structure, the optic organelle, composed of a large central hyaline structure, the lens, which is surrounded by a dense network of nerve fibrillae, the retinella. In hanging drops the lens was found to focus light in the region of the retinella irrespective of the direction of the rays.

These cells are similar in structure and function to the visual cells in leeches. Available data indicate that these cells function as photoreceptors and that the fibrillae of the retinella are the direct receptors of light stimuli.

Pigment is not associated with the photoreceptors in a way that suggests direct functional relationship, but there is a subepidermal pigment layer through which pinhole windows admit light along the path of nerves to each of the nerve enlargements containing photoreceptor cells. These windows open in such directions as to determine the direction of withdrawal of the worm.
The multiple testis in diemyctylus
Authors: Humphrey R. R.
Published: February 2005

A study of the development and seasonal changes of the testis in Diemyctylus viridescens shows that accessory testicular lobes arise as follows: Emptying of the caudal zone of the testis at mating is followed by degeneration of the lobules (tubules) of that region, reducing it to a slender cord consisting chiefly of duct system and residual spermatogonia. A regeneration of lobules at the distal end of this cord later gives rise to the second or accessory lobe.

Accessory lobes develop in immature males after a similar reduction of the caudal end of the testis through spermatogonial degeneration or an abortive spermatogenesis. The caudal germ‐cell cord thus formed is comparable to that resulting from extrusion of spermatozoa, and the development of new lobules at the distal end of this cord gives rise to a second lobe as in adult males. There is no evidence of the formation of a multiple testis by outgrowths from the primary lobe or by the junction of several lobes originally separate.

A multiple testis occurs in Urodele species exhibiting two peculiarities of the spermatogenetic pattern: (1) a slow spermatogenetic wave and, (2) delayed regeneration of lobules emptied at mating or by degeneration of their germ cells. The number of lobes is correlated with the age of the individual. In Diemyctylus under 6 cm. the first accessory lobe has not yet developed.
The embryology of cryptobranchus allegheniensis. III. Formation of the blastula
Authors: Smith Bertram G.
Published: February 2005

In the blastula the region of accelerated cell division is on the ventral side of the egg, nearly opposite the site of the future beginning blastopore. The ventral wall of the blastocoele is thicker than the dorsal. In the very early gastrula a new region of accelerated cell division appears in the vicinity of the dorsal lip of the blastopore.

A downward movement of material comprising the marginal zone of micromeres and the portion of the wall of the blastocoele immediately above it occurs during all the later blastula stages and continues until this material is carried below the level of the equator and involved in the process of gastrulation. On the dorsal side of the egg, this movement is more rapid than on the ventral side.

In the late blastula stage there are evidences of growth in the region of smaller micromeres. In the very late blastula, a vertical groove appears at the dorsal margin of the floor of the blastocoele; this groove is believed to indicate the operation of factors concerned with gastrulation.

In connection with the first nuclear division, evidences of cytoplasmic activity leading to the formation of the first cleavage furrow are described. As the blastomeres become smaller, progressive changes take place in the distribution of their cytoplasm.
Reversal of ciliary action in paramecium caudatum
Authors: Mast S. O. , Nadler J. Ernest
Published: February 2005

Monovalent cation salts induce reversal in the direction of the stroke of the cilia; bivalent and trivalent cation salts with a few exceptions do not. Some acids induce reversal, others do not.

The duration of reversed action varies with the kind of salt and with the concentration. As the concentration increases, the duration of reversed action increases to a maximum and then decreases to zero.

Bivalent and trivalent cation salts neutralize the effect of monovalent cation salts. The relative amount required varies with the kind of salt used and with the concentration.

The amount of a given salt required to neutralize another salt is not proportional to the concentration of the salt neutralized. Weber's law does not hold.

The results seem to indicate that ciliary reversal is associated with differential adsorption and consequent changes in electric potential, but that there are also other factors involved.
Caste formation in the termite genus termopsis
Authors: Heath Harold
Published: February 2005

In Termopsis nevadensis only soldiers are produced during the first three or four years. When a normal colony comprises approximately twenty inhabitants, the first adult soldier is probably in the fifth instar; the second, somewhat larger, certainly is in the sixth. Later, others are produced in the seventh, and after the reproductive caste becomes differentiated, with about 450 inhabitants, they are in the eighth. Finally, in very old communities, some, at least, are in the ninth. The winged insect invariably is in the eighth.

No sign of wings exists until the reproductive caste appears, after which every member of the sixth, and probably the fifth, instar possesses small, yet distinct, wing rudiments. These persist and enlarge in the later stages of the reproductive caste, and, of smaller size, they frequently occur in the soldier nymph and to a less degree in the adult. The third‐form adult is probably a sexually mature soldier nymph; the second‐form adult seemingly has the same origin and, though possessing wing buds, it does not belong to a special caste.

Measurements of scores of recently hatched young disclose no differences other than those of ordinary variation, either in width of head, number of antennal segments, or size of brain and gonad. The first visible signs of caste differentiation appear at a relatively late stage. All of the instars are described in detail and the later ones are compared.
Oxygen consumption of individual pupae during metamorphosis
Authors: Taylor Ivon R.
Published: February 2005

The rates of oxygen consumption of single pupae of blowflies (Phormia terraenovae, Phormia regina, Lucilia sericata), of the flesh fly (Sarcophaga sarracenioides Aldrich), of the Mediterranean flour moth (Ephestia kuehniella), and of the bee moth (Galleria mellonella) during metamorphosis, until emergence, have been determined. The record for each pupa, with the exception of those of blowflies, is practically continuous day and night during the period of pupal development which lasted from 140 to 300 hours, according to the species, at the temperatures used. During pupal development there is first a period of decrease in rate, which is later followed by a steady increase until a short time before emergence, when a sudden decrease occurs.

The ‘oxygen curves’ of the blowfly pupae (Diptera) are quite different from those of the flour‐moth and bee‐moth pupae (Lepidoptera), although all are of the same general U‐shaped type. There are strong indications of a specific difference in the curves of the blow‐fly pupae. The flour‐moth pupae curves differ slightly from those of the bee‐moth pupae. During the major part of development the rates of O2 consumption of pupae of both sexes of bee moth and flour moth are about the same, but near the end of metamorphosis the females have higher rates than the males. No such sex difference appears among the dipterous pupae used.
Studies on the Balantidium from the guinea‐pig
Authors: Scott Miriam Jackson
Published: February 2005

Observations indicate that this Balantidium from the guinea‐pig is Balantidium coli, the form found in the pig and man. The lengths and breadths of this Balantidium and the ratios of length to breadth are very close to the measurements and ratios given by McDonald for B. coli. When plotted, the body lengths of the guinea‐pig parasites appear in two groups, the smaller individuals being the exconjugants. Many of these exconjugants resemble Neiva's B. caviae. The structure of the Balantidium from the guinea‐pig is essentially identical with that of B. coli as given by McDonald.

Fission and conjugation of this ciliate follow the general course found in a number of other ciliates. During fission the micronucleus divides and the daughter micronuclei migrate to each end of the macronucleus before the latter divides. In conjugation there are two divisions of the micronucleus, one of these nuclei dividing to form the pronuclei. Pronuclear exchange and fusion are followed by a heteropolar division of the synkaryon, resulting in the formation of the new macronuclear and micronuclear anlagen.

The parasite was found in the intestinal tissue of the host. No reproductive stages were found in the cysts. New hosts are invaded through contamination of the food and drink with the cysts.
The metabolism of amino‐acids by Paramecium caudatum
Authors: Emery Frederick E.
Published: February 2005

The object of the present study is to determine by quantitative means the rate at which a given number of paramecia can utilize the various amino‐acids and to study factors influencing this rate.

The method consisted in testing the rate of utilization of isolated and mixtures of amino‐acids by a known number of Paramecium caudatum. The amino‐acids were used in 0.1 per cent solution and were tested, by the Henriques‐Sörensen formol titration method for amino‐acids, at the beginning and after the paramecia had lived in these amino‐acids for twelve hours. The difference between these two tests, figured in percentage, is considered as the amount utilized by the paramecia. The part played by bacteria was found to be negligible when isolated amino‐acids were studied. The influence of temperature on the rate of utilization of the amino‐acids has been studied, and the results show a direct relationship between the two.

The rate of utilization was decreased by anaesthetics and nitroglycerin. A careful study has been made of a number of isolated amino‐acids and the rate of utilization of each discussed in relationship to the others studied. An explanation of why one amino‐acid was used more than another amino‐acid was sought for, but not found. A detailed discussion of the above points has been presented in the body of the paper.
The breeding season of the opossum (Didelphis virginiana) and the rate of intrauterine and postnatal development
Authors: Hartman Carl G.
Published: February 2005

The breeding season of the opossum at Austin, Texas, begins in January, following a three months' anoestrous period. The modal point for ovulation days is reached in the third week. The rate of intra‐uterine development was investigated chiefly by surgical removal of one uterus, noting the stage attained by the ova therein and allowing the surviving uterus to incubate its ova a precalculated period of time. Unique charts epitomize the results. The primitive‐streak stage is completed, the medullary groove and chorda begin at seven and one‐half days post coitum, seven days post ovulationem, leaving only five and one‐half days' actual development of the embryo to birth. The rate of development is compared with Eutherian mammals.

The curve of postnatal growth has the shape of embryonic growth curve of higher mammals. The eyes and lips open, at about fifty days (young the size of mice). At this time the young leave the teat for the first time, but are not weaned for about thirty days more. Soon after weaning, the mother may become pregnant again. At ninety to one hundred days (young size of large rats), the young may begin to shift for themselves.
The history of the germ cells in the domestic fowl
Authors: Goldsmith Joseph B.
Published: February 2005

Material of the domestic fowl of appropriate ages, ranging from twelve hours' incubation to the adult bird, was prepared for the purpose of studying the production and development of the germ cells.

The primordial germ cells arise in the extra‐embryonic region anterior to the head fold in the region of the zone of junction during the primitive‐streak stage. These germ cells migrate, through the blood stream, to the region of the future gonad, where they develop into the definitive germ plasm.

There is no widespread degeneration of the primordial germ cells after their arrival in the gonadal region, nor is there any widespread transformation of somatic cells into definitive germ cells.
Binary fission and endomixis in the Trichodina from tadpoles (Protozoa, Ciliata)
Authors: Diller William F.
Published: February 2005

This peritrichous ciliate lives as an ectocommensal on the skin and gills of anuran tadpoles. Its relation to described species of Trichodina is doubtful. This study was made almost exclusively on fixed and stained material. Binary fission is similar to that in other ciliates. The horseshoe‐shaped macronucleus condenses, then divides amitotically. The single small micronucleus forms a spindle containing between four and six chromosomes.

Endomixis is of high incidence in the free‐living Trichodinae. Encystment was not observed. At the onset of endomixis, the macronucleus disintegrates into fragments which persist throughout the process. The micronucleus undergoes three rapidly succeeding mitotic divisions to form eight nuclei. There is no evidence of chromosome reduction during these divisions. Seven of the nuclei differentiate into macronuclear anlagen; the eighth becomes the functional micronucleus. Successive cell divisions—before each of which the micronucleus divides—distribute macronuclei to daughter cells. Variations from the regular process of endomixis may arise, 1) by precocious division of endomictic parents; 2) by extra divisions of the micronucleus; 3) by less than the usual number (three) of divisions of the micronucleus; 4) by hypertrophy and early differentiation of the micronucleus into macronuclei; 5) by unusual segregation of nuclei to daughters, and, 6) from miscellaneous causes.

The significance of these variations is discussed in connection with the possible origin of bimicronucleate and amicronucleate races.
The chromosome cycle in the rotifer asplanchna amphora
Authors: Whitney David D.
Published: February 2005

The diploid number of twenty‐six chromosomes was found in the mature parthenogenetic female‐producing eggs and also in the somatic cells of the female embryos developing from such eggs. In the maturation stages of a few of these eggs the chromosomes were markedly larger than in the corresponding stages of the majority of the eggs. Whether this size difference of the chromosomes is correlated with male‐ and female‐producing individuals has not been determined. The mature parthenogenetic male‐producing eggs contain the haploid number of thirteen chromosomes, and this number was found also in the somatic cells of the young male embryos. The mature sexual eggs contain thirteen chromosomes.

In spermatogenesis the secondary spermatocyte divisions are usually omitted and the secondary spermatocytes develop directly into the motile spermatozoa containing thirteen chromosomes. A few, however, of the secondary spermatocytes divide, forming spermatids containing fewer than thirteen chromosomes. These cells develop into the non‐motile and rudimentary spermatozoa.

The motile spermatozoa containing thirteen chromosomes unite with the parthenogenetic male‐producing eggs containing thirteen chromosomes, thus producing the fertilized eggs with the diploid number of twenty‐six chromosomes. These fertilized eggs develop into female‐producing females which reproduce parthenogenetically.
Sex dimorphism in the syrinx of the fowl
Authors: Appel Fred W.
Published: February 2005

This study concerns the voice box or syrinx of the fowl in its possible relation to sex. Although neither hens nor capons crow, ovariotomized hens have been known to do so. It appears that a slight sexual dimporphism exists in the syrinx of certain fowls, and it was thought that a particular form might be essential to the act of crowing. However, no sexual dimorphism is apparent in the syrinx of the Brown Leghorn fowl.

The syringeal structures of crowing birds (cocks and ovariotomized females) contain no features which cannot be demonstrated in normal females. Variations were found in the syrinx in this breed and in other breeds, but they had nothing to do with sex. There is a gradual ossification with increasing age and size. It may be concluded that there is no apparent reason why the female fowl should not crow, provided it had the instinct to do so properly developed. The sex hormones, if they act in voice production, must act entirely through the conditioning of the central nervous system.
Studies of parajulid diplopods. I. The development of the external sexual structures of Parajulus impressus say(8)
Authors: Hefner R. A.
Published: February 2005

A description of the gross embryology of the sex apparatus of a common diplopod, the corn millipede. The life‐cycle of this animal involves eleven instars extending over a period of three years.

In the male the true first legs are shed at the ninth ecdysis and the large clasping appendages are substituted through the last three instars. In the region of the second body somite the fused coxal plate and the penes are developed at the final molt; the second appendages are reduced at this time. The greatest changes occur in the region of the seventh somite, where the legs are shed about the eighth ecdysis and the gonopods developed through the remaining instars. It is evident that these gonopods arise as a modification of the sternites of the seventh somite.

In the female the second legs are reduced to vestiges at the final molt. The structures at the mouth of the oviducts are developed from the surrounding tissues and the modified sternites of the reduced second legs. These changes are in progress as early as the seventh instar, but the greatest changes occur at the final ecdysis.
On the arterial system of the lizard Uromastix hardwickii
Authors: Bhatia M. L.
Published: February 2005

The arterial system of Uromastix hardwickii retains many primitive features and shows great resemblance and relationship to that of Sphenodon. The heart is typically reptilian. Two systemics and a pulmonary arch arise from the ventricle. The conus arteriosus is absent. The carotids arise together from the right systemic by means of a small common carotis primaria. A very well‐developed ductus caroticus connects each carotid with the systemic arch of its side. The ductus arteriosus (ductus Botalli) is absent.

The dorsal aorta is formed by the union of both the systemic arches. The left systemic joins entire while the right one, which is termed systemicocarotid trunk, gives off the carotids, the vertebral, a single subclavian, and two pairs of parietal arteries, before the union. Anterior epigastric arteries are altogether absent. The dorsal aorta gives off fifteen pairs of parietal arteries which are segmentally arranged. All the main branches supplying the alimentary canal and other viscerala organs arise independently of one another, there being no such combination as is found in Varanus.
The ovarian chromosome cycle in a mixed rat strain
Authors: Swezy Olive
Published: February 2005

In the ovary of the rat the ova arise by proliferations from the germinal epithelium, all cells of which are potential ova. This proliferation begins with the differentiation of the gonad, and may last as long as 369 days postpartum. The embryonic ovary is filled with ova which pass through the typical maturation phases. This continues until five days after parturition. These ova degenerate, none being found in the ovary of the twenty‐day rat. After the fifth day postpartum, nuclear development in the ova changes until, by the twentieth day, no typical maturation phases are present. With the degeneration of the embryonic ova the ovary takes on the adult structure.

The ovary of the adult female rat shows a modified type of meiosis in the germ cells, while that of the embryo shows the typical phases, indicating that this is the primitive type, with the modified form an acquired characteristic.

Ova in a single rat may show both twenty‐one and thirty‐one chromosomes.

Follicle cells are formed from the cells of the germinal epithelium and, like the sex cells, may have both forty‐two and sixty‐two chromosomes in a single follicle. The lutein cells also show both forty‐two and sixty‐two chromosomes in a single corpus luteum. The chromosomes of the lutein cells enlarge with the expansion of the cell to a size greatly in excess of the chromosomes of the somatic cells. The theca interna is derived from the tunica albuginea.
A study of the function of the epididymis. II. The importance of an aging process in sperm for the length of the period during which fertilizing capacity is retained by sperm isolated in the epididymis of the guinea‐pig
Authors: Young William C.
Published: February 2005

Following the isolation of sperm in the epididymides of male guinea‐pigs by the separation of this organ from the testis, the animals were found to remain fertile for periods varying from twenty to thirty‐five days, whether they were allowed to mate but once during this period, or five times during the period, or twenty times during the period. Motile sperm were found as long as fifty‐nine days after the operation. It was concluded, on the basis of these data, that an aging process which sperm isolated in the epididymis undergo is more important than the number of matings (up to at least nine or ten) in the determination of the period during which sperm motility is retained and in the determination of the period during which fertilizing capacity is retained.

If the behavior of sperm isolated in the epididymides can be taken as an indication of the processes of sperm development which occur normally, the epididymis would seem to be an organ in which sperm may at one time be attaining an optimal functional state and may at another time be aging and becoming incapable of functioning. The possible significance of this suggestion for the rǒle of the epididymis in sperm development and for the history of sperm after they leave the testis is discussed.
The origin of neutral fats from the Golgi apparatus of the spermatid of the dog
Authors: Bell A. W.
Published: February 2005

By the use of a new technique it was possible to demonstrate the Golgi granules about the idiosome of spermatids and in the so‐called Golgi bead of the mature spermatozoon. Other osmiophile granules in the cytoplasm, assumed to be Golgi granules, aggregate during metamorphosis into groups which formed neutral fat spheres, giving stains with both sudan III and scharlach R. Evidence is adduced supporting the view that the Golgi apparatus is a lipin and probably a phospholipin. The fat spheres produced are probably a result of fatty degeneration in the residual body of the spermatid. They may also serve as the source of lipin in Popa's ‘Lipo‐gel’ phenomenon.
Photoreceptors in Mya arenaria, with special reference to their distribution, structure, and function
Authors: Light V. Earl
Published: February 2005

Experimental studies on the responses to light in Mya arenaria L. indicate that photosensitive tissue is located somewhere near the inner surface of the siphon and that the siphon is sensitive throughout its entire length.

A histological study of the siphon shows cells of a special type in the photosensitive region, which are most abundant where the inner surface of the siphon is most sensitive. They are found throughout the length of the siphon, just beneath the inner epithelial layer, around both the incurrent and excurrent siphons. They receive nerve elements from branches of sixteen large nerves.

Each cell contains a characteristic inner structure, the optic organelle, composed of a rather large hyaline structure, the lens, which is surrounded by a network of nerve fibrillae, the retinella. Light rays, reflected from a flat mirror through the lens in these cells, are brought to a focus in the region of the retinella, irrespective of the direction of the rays.

The cells are similar in structure and function to visual cells in leeches and photoreceptors in the earthworm. Available data indicate that they function as photoreceptors and that the fibrillae of the retinella are direct receptors of light stimuli.

Pigment spots found in considerable number on the distal third of the siphon, and thought by some to be eyespots, are, owing to simulation of the background, probably protective in nature, rather than functional in photoreception.
The formation of the sex glands and germ cells of mammals. IV. Continuous origin and degeneration of germ cells in the female albino rat
Authors: Hargitt Geo. T.
Published: February 2005

The current view in mammals is that ova are formed in the embryo in large numbers and stored in the ovary as a reserve to be drawn on through adult life; they may persist for long periods ina latent condition, a few resuming active development at each recurring oestrous period; new ova are not and cannot be added.

An alternative hypothesis has been presented by several authors: New ova are formed throughout life, from the embryonic period through the time of sexual maturity; each ovum so produced must at once begin its growth and development of die; long latency of oocytes and primary follicles is not possible and does not occur. There is a constant degeneration of most follicles, and only a few come to ovulation. A study of the albino rat presents evidence which is consistent with the second view and supports it more strongly that it does the older hypothesis. Similar evidence is found in other mammals. It seems probable that the newer hypothesis is the correct one, at least in some mammals; further investigation may show it to be of general application.
The natural history of Bugula flabellata at Woods Hole, Massachusetts, including the behavior and attachment of the larva
Authors: Grave Benjamin H.
Published: February 2005

The breeding season of Bugula flabellata extends from June 10th to November 15th. The young embryos develop in brood pouches (ovicells) and are finally expelled from the colony as swimming embryos. They come from the colonies at dawn or early morning. After a free‐swimming period of four to six hours, each larva becomes attached and after a profound metamorphosis which involves the loss of larval organs, it develops into the bryozoan colony by budding.

The larvae at first are positive to light, but become negative before attachment. Their behavior is described in detail and the mode of attachment is explained.

After the larva has become attached a period of rapid growth by budding ensues. The rate of growth is given in a table in which it is shown that the first individual of the colony is completed in two days and that a new series of buds is formed every two days. There are eight or ten individuals after one week and over a hundred in two weeks. In one month the colony is half‐grown and becomes sexually mature. A colony becomes senescent in three months, when it measures 112 to 134 inches in diameter.

Younger colonies hibernate successfully and resume growth in early May, when new polypides are formed.
The arterial system of Palaemonetes
Authors: Brody Michael Steve , Perkins Earle Bryant
Published: February 2005

Color changes in Palaemonetes had been found to be inhibited in the whole abdomen by occluding the dorsal abdominal artery. Inasmuch as these chromatic responses are brought about by means of circulating hormones, it should be possible, in view of early anatomical findings, for specific substances to reach the abdomen by way of the ventral abdominal artery which has been described for so many decapod crustaceans. This paper reports a degenerate ventral abdominal artery and a ventral continuation of the dorsal abdominal artery, the latter thus being distributed to practically the entire abdomen and therefore chiefly responsible for abdominal color‐change phenomena.

A method is given for injecting the arteries of small crustaceans, and the entire arterial system of Palaemonetes is described and figured. Several hitherto unreported vascular structures are noted: a plexus of blood vessels surrounding the supra‐oesophageal ganglion, certain branches of the ophthalmic artery leading to the eyes, and various branches of the dorsal abdominal artery in the region of the telson and uropods. The forward flow of blood in the ventral portion of the abdomen in decapod crustaceans is held to be unique.
A histological basis to explain constant differences in action‐current response from certain points on the retina of the horned toad, Phrynosoma cornutum
Authors: Keeler Clyde E.
Published: February 2005

The retina of Phrynosoma cornutum bears fovea, pecten, and many varieties of cones. The light band visible in fresh retinae beneath the slit of the eyelid corresponds to a zone of action current responses characterized by a low ‘B’ rise (negative response of Chaffee.) The lack of response from pecten and fovea is due to leakage and failure to tap ganglionic fibers.

Relief maps for ‘on’ and ‘off’ effects of the ‘B’ rise were prepared.

Diagrams of retinal response in cross‐sections were compared with corresponding curves showing density of cone distribution. In general, the height of response is inversely proportional to the density of cone distribution.

The potential change due to photochemical reaction in the average rod is on the order of 23 billionths of a volt for the ‘on’ effect and 11 billionths of a volt for the ‘off’ effect.
The morphology of Spironympha, with a description of a new species from reticulitermes hesperus Banks
Authors: Brown George V. E.
Published: February 2005

Spironympha is discussed as valid genus. It was described by Koidzumi ('16); later it was redescribed by the same author as Microspironympha ('21). Therefore, according to the rules of nomenclature, it is Spironympha.

The genus is compared with the related genera: Spirotrichonympha, Holomastigotes, and Microjoenia.

Spironympha is characterized by four flagellar bands which are spirally wound around the anterior part of the body; these bands occur only in the anterior end, whereas in Spirotrichonympha they extend almost to the posterior end. The parabasals are few in number, and they are attached to the basal granules of the flagellar bands; the anterior end is clear and almost free from cytoplasmic granules; and there are twenty to thirty anterior flagella which are attached to the base of the centroblepharoplast or to the basal granules of the flagellar bands. An axostyle is present.

No centrosome occurs within the nucleus, but the centroblepharoplast has this kinetic function.

Spironympha ovalis is described as a new species. It is ovoid; the average size is 38 μ to 44 μ. An axostyle is present. The host is Reticulitermes hesperus Banks.
The evolutional significance of the chromosomes of Aphididae
Authors: Shinji Orihay
Published: February 2005

An investigation into the number of chromosomes in thirty‐seven species of Aphidiae belonging to twenty‐seven geaera has shown that there is but one sex chromosome in the male cells of all but one species of Aphididae. That exceptional species is Euceraphis betulae Koch.

The number of chromosomes and body characters are so closely correlated that we can safely judge the evolutional scale of any aphid by its number of chromosomes.

In Aphididae the least number of chromosomes seems to be the most primitive.

The number of chromosomes varies with the genera. The highest number is 1811+ X = 37 chromosomes, the lowest being 211+ X = 5 (diploid in male).

The increase in the number of chromosomes seems to have been brought about by transverse divisions of the primitive chromosomes.

The genus Tuberolachnus with 311+ X = 4 elements (♂) represents altogether different chromosomes characters from the genus Pterochlorus with 8 elements.

In the genera Periphyllus and Calaphis there are species with a smallm‐element which is bivalent.
The vacuome of the flagellate Chlamydomonas
Authors: Hall Richard P. , Nigrelli Ross F.
Published: February 2005

A vacuome (‘Golgi apparatus’) consisting of small globular inclusions has been demonstrated in Chlamydomonas sp. These inclusions may be seen in the living, unstained organism; they are stainable vitally with neutral red; they have been stained vitally with neutral red and then blackened with osmic vapor under direct observation, and they have been impregnated by osmic and silver methods without previous treatment with neutral red.

The reaction of these inclusions to the iodin test for starch suggests that they may play some rǒle, possibly one of storage, in the cycle of starch metabolism.
Notes on the postnuclear, acrosome‐seat granules, and ‘vacuome’ in Desmognathus fusca spermatogenesis
Authors: Gatenby J. Brontë
Published: February 2005

The acrosome in Desmognathus, Spelerpes, Plethodon, salamander, Amphiuma, etc., is attached to the nucleus in connection with an acrosome seat, which forms a shallow cup, traced back to a number of granules in the early spermatid. A postnuclear plate is present in the above‐mentioned urodeles, and is derived from a small number of minute granules which assemble in the spermatid and become fixed onto the nuclear membrane. The centrosomes of the spermatid are visible intravitam. The ‘vacuome’ is formed of minute neutral‐red‐staining globules embedded in the idiozome. No connection appears to exist between mitochondria and Golgi bodies, as is postulated by the vacuome‐chondriome hypothesis (Parat).
Insect development. II. Mitotic activity in the grasshopper embryo
Authors: Slifer Eleanor H.
Published: February 2005

The onset of hibernation in Melanoplus differentialis eggs kept at high temperatures is accompanied by a fairly abrupt cessation of cell division. The total number of mitotic figures present in the different individuals of a series of embryos of this grasshopper, from eggs kept for eighteen to twenty days at 25°C. from the time of saying, was found to vary between 1000 and 4400. In contrast to the conditions found in eggs of this age, embryos from eggs kept twenty‐seven days at 25°C., as well as those older and still in the hibernating state, contained few or no dividing cells. During the course of the work it was found that, in rare cases, hibernation failed to occur, a few or many of the eggs developed without a pause when kept at 25°C., and hatched at approximately the thirty‐eighth day. The detection of variations in the rate of mitotic activity over short periods, as originally planned, was found impossible, because of the comparatively small number of embryos used.
Studies on the comparative histology of the digestive tube of certain teleost fishes II. A minnow (Campostoma anomalum)
Authors: Rogick Mary Dora
Published: February 2005

This paper presents a study of the normal histology of the digestive tract of an herbivorous teleost, the minnow Campostoma anomalum (Raflnesque). The tunics of the buccal cavity, pharynx, esophagus, and intestine are described; particular attention is given to the mucosa because of the specializations occurring in that coat, such as taste buds, goblet cells, callous pad, etc. Because of the very decided anatomical and histological differences existing between the anterior and posterior regions of the pharynx, due to the presence of a callous pad and pharyngeal teeth, it has been deemed advisable to consider the pharynx as divisible into an anterior and a posterior region. Thyroid tissue was found in the submucosa of the anterior pharynx. No gastric epithelium was demonstrated, the ‘intestinal bulb,’ the only enlargement of the coelomic portion of the digestive tube, being lined with epithelium presenting only minor differences from that found in the coiled tubular intestine.
The ontogenetic history of the mitochondria of the hepatic cell of the white rat
Authors: Smith Dorothea M.
Published: February 2005

This work was designed to determine the ontogenetic variability of the morphology of mitochondria of the hepatic cell.

The mitochondria of the cells of the hepatic diverticulum are minute spheres. These spheres enlarge, become associated, forming beaded filaments, which in turn become smooth filaments, the process culminating in the twenty‐day fetus. There is no individual or lobular variabillty in fetuses of a given length. One‐half day before birth the above process is reversed, so that separate spheres are found in the eight‐ to twelve‐hour young. This enlargement and enspherulation are accompanied by an accumulation of large quantities of glycogen. After this age, the spheres become associated into beaded filaments again and the glycogen disappears, the cycle ending at thirty‐three hours. From two to eight days of age there is great individual variability.

Mitochondrial morphology characterstic of the adult is first found in the fourteen‐day young, when cells contain long, smooth or beaded filaments, rods, and spheres. There is no lobular variation as to types of mitochondria, but only in numbers, the cells around the central vein containing fewer mitochondria than other cells of the lobule. Variation between individuals after birth is due to something other than age, type of food, period of digestion, and length of starvation. Fat is formed within spherical chondriosomes.
Cytoplasmic structures in the ganglion cells of certain Orthoptera, with special reference to the Golgi bodies, mitochondria, ‘vacuome,’ intracellular trabeculae (trophospongium), and neurofibrillae
Authors: Beams H. W. , King Robert L.
Published: February 2005

The Golgi bodies of the nerve cells of the grasshopper are discrete elements composed of an osmiophilic cortex and an osmiophobic medulla. When seen in face, they appear ring‐like, semicircular, or crescentic. The osmiophilic portion is interpreted as the homologue of the classical Golgi apparatus and may under certain conditions be dissolved away, leaving clear spaces homologous to the canalicular apparatus (negative image of Golgi apparatus). When the osmiophilic portion is dissolved, the osmiophobic portion remains as a definite structure which apparently has no homologue in the classical Golgi apparatus. The mitochondria are granular, rod‐like, or filamentous and show no transformation into Golgi bodies. Neutral‐red bodies (‘vacuome’) of two kinds have been observed, neither of which is a constant preformed structure or has any relationship to the Golgi bodies. Prolongations of the capsule (trophospongium?) of the nerve cell penetrate into the cell approximately one‐third the distance to the nucleus. These are interpreted as supportive rather than nutritive in function. A basket‐like net of neurofibrillae surrounds the nucleus. It is suggested that the networks described as Golgi apparatus in certain invertebrate nerve cells may really consist of these neurofibrillae.

The conclusion of Parat that Golgi material consists either of mitochondria or ‘vacuome’ is rejected. The idea that all structures in the living cell which stain with neutral red (‘vacuome’) are homologous is also rejected.
The nutrition of glochidia during metamorphosis. A microscopical study of the sources and manner of utilization of the nutritive substances
Authors: Arey Leslie B.
Published: February 2005

Part of the nutriment of metamorphosing glochidia is supplied by the cellular host tissue, bitten by the larvae during attachment. Some of this is taken up piecemeal by the mantle cells and digested intracellularly. The coarse granules that first pack the mantle cells are apparently the precursors of a digestive secretion, some of which escapes into the mantle cavity. Here it also causes the prompt dissolution of additional utilizable host tissue.

Another source of nutriment is furnished by the provisional larval adductor muscle which undergoes degenerative changes in situ, then fragments, and finally is carried away bit by bit by amoeboid cells. These turn over their muscle content to the larval mantle, where the particles are further reduced beyond recognition. The mantle remnant itself is finally sacrificed and doubtless becomes an additional source of nutriment.

The gut serves as an organ of nutrition throughout the last two‐thirds of the parasitic period. It appears to admit and digest pieces of the adductor muscle and certain unidentified particulate matter. In addition, the gut, like the definitive mantle and other organs, doubtless absorbs tissue transudate from the host.

Special vascularization of the host tissue to facilitate the passage of nutriment from host to parasite does not occur, yet there is no reason to doubt that an appreciable part of the larval nutrition results from transuding tissue juices.
Coordination of ciliary movement. II. The effect of temperature upon the ciliary wave length
Authors: Lucas Alfred M.
Published: February 2005

The ciliary wave length is a constant in the temperature range of 10° to 30°C. and in Modiolus demissus has the average value of 13.1 μ. Comparison of these data for ciliary coordination with those of nerve conduction probably indicates that the two physiological processes possess certain properties in common. The cells which bear the cilia are 12.75 μ long and the variation in ciliary wave length and cell length is about the same, which may indicate a possible cytophysiological relationship between the two.
Comments on the origin of the midgut in insects
Authors: Richards A. Glenn
Published: February 2005

Reviews the question of the origin of the midgut of insects with its diverse appearances and interpretations. Without doubt the midgut epithelium in some insects is derived from the lower layer, but in other insects from the tips of the stomodaeal and proctodaeal invaginations. The question of its origin seems to be “a function of the position within the whole,” and best understood from a standpoint of the time of determination of the parts involved. Maps illustrating the prospective significances of the principal types are included and discussed.
Studies on the life cycle of the snail, Viviparus contectoides
Authors: Van Cleave Harley J. , Lederer Ludwig G.
Published: February 2005

More than 3700 individuals of Viviparus contectoides from the Illinois River, near Peoria, Illinois, and from the Erie Canal in central New York, have been the subject of statistical and biological analysis as periodic quantitative samples to secure information on the life cycle. Sexes are easily distinguished through tentacular differences. Shells show marked sex dimorphism of size. Males reach a maximum height of 25 mm.; females may exceed 40 mm. Distribution curves, checked by experimental data on another species of the same genus, give evidence that males live normally about one year, while females may live three years. Differences in sex ratio are attributable to differences in life span and to changes in environmental factors producing aggregations of members of one sex.

In central New York, the parturition period seems to begin to March and terminates in June. In central Illinois it extends from February into May. The uterus of a gravid female contains eggs, embryos, and shelled young in a graded series. At birth, the young shell contains one and one‐half whorls and has a height of approximately 3.8 mm. Color bands are present on the shell three months before birth. Initial growth rate is extremely rapid. In less than three months the largest of the new generation are as large as the smallest of the parent generation. Graphs given show seasonal changes in the population.
A study of the cytoplasm in insect ova
Authors: Payne Fernandus
Published: February 2005

The cytoplasm of the ova of ten species of insects, distributed among the Hemiptera, Coleoptera, Hymenoptera, Diptera, Orthoptera, and Neuroptera, has been studied. The Golgi bodies and chondriosomes were traced. They increase in number by fragmentation, but whether they may also arise de novo was not determined. They play no visible part in the formation of yolk or fat or any other structures or substances. Fat and yolk apparently arise independently in the cytoplasm. Vacuoles, which may stain with neutral red, may be present, but they are independent of the Golgi bodies. There is no vacuome in the sense in which Parat and others use the term. The Golgi bodies and chondriosomes are interpreted as substances rather than structures and as intermediate products of metabolism. Other bodies of unknown nature and function are present. The yolk nucleus of Gelastocoris is interpreted as a synthetic center.
The architecture of the pectoral appendage of the dogfish
Authors: Howell A. Brazier
Published: February 2005

The m. trapezius, with both brachial and branchial functions, is in seeming series with the mm. interarcuales laterales. The intrinsic muscles of the fin occur as a dorsal extensor sheet and three (or four) ventral flexor components. The spinal nerves, uncomplicated by extensive anastomoses, which supply the fin, clearly show that in the dogfish the fin muscles are derived not from dorsal and ventral elements, but from anterior and posterior, or protractor and retractor elements. The nerves prove that from the original protractor musculature only the anterior portion of the present flexor group is derived, while the original retractor musculature has become all of the extensor and the posterior part of the flexor series. Faradic stimulation of the live animal is satisfactory, although there is much variation in the sensitivity, particularly of different muscles.
Observations on spermiogenesis in sciara coprophila
Authors: Doyle William L.
Published: February 2005

The mitochondria in the male germ cells of Sciara exhibit peculiarities as regards both morphological characteristics and distribution. In form. they show superficial similarity with those of some of the scorpions, while their distribution may be peculiar to the genus and depend on unusual meiotic divisions.
Basophile (mast) cells in the alimentary canal of salmonoid fishes
Authors: Bolton Lloyd L.
Published: February 2005

Basophiilic granule cells which occur in vast number in the connective tissue throughout all regions of the alimentary canal of sockeye salmon and speckled trout are interpreted as histogenous mast cells. Their occurrence in several other species is noted. None could be found in blood or in any other organs. Their development from mesenchymal cells is described (speckled trout). Their function or possible relationship to functional conditions of the tract could not be determined. Experiments showed the granules to be quickly destroyed by acids and bases but not by water in the fresh condition, but they were extremely stable structures after Helly fixation. In living cells, the granules are probably fluid, and consist of proteins. There was no indication of the granules being composed of mucin, or of the cells being degenerated forms. The granules are basophilic at all times.