bluuebunny/crossref_metadata_2025 huggingface dataset:
Prenatal growth of swine
Authors: Warwick B. L.
Published: February 2005

Fetuses from forty‐three gravid uteruses from sows of known breeding dates, as well as from 448 uteruses with unknown breeding dates, were studied. Growth curves are given for weight and length of fetus and for weight of fetal membranes. The weight of the fetus first reaches that of the fetal membranes between the sixtieth and seventieth days of pregnancy. Degenerate fetuses were found in 3.68 per cent of the cases. They were found at all stages of gestation. Size of litter was found to decrease from 11.4 at the twentieth day to 6.8 at the 110th day. Also, the calculated per cent of ova lost up to each ten‐day stage tends to increase as gestation advances. Crowding was found to be an important factor, but probably not the only factor, in causing degeneration. Genetic factors were probably responsible for part of the resorbing fetuses.

In the study of the normal fetuses, significant correlations were found between fetus length and weight of fetal membranes, as well as between fetus weight and weight of fetal membranes. Lower correlations, but probably significant, were found between total distance (spacing) between fetuses in the uterus and weight of fetal membranes. Correlations between size of fetus and total distance between fetuses were very low. As in the case of the degenerates, crowding has an important relationship to size of fetus, but is probably not the only factor involved.
Growth of paramecia in pure cultures of pathogenic bacteria and in the presence of soluble products of such bacteria
Authors: Philpott C. H.
Published: February 2005

Virulent hay‐infusion cultures of Bacillus pyocyaneus are toxic to pure‐line races of three species of paramecia, but these races may acquire a tolerance for this toxic agent. Races with acquired tolerance have been grown for long periods of time in toxic, pure cultures of B. pyocyaneus by means of the daily‐isolation culture method, and here the average division rate is as high as, or higher than, in the chance‐mixed bacterial cultures in which these protozoa are usually maintained in the laboratory. The tolerance is lost, however, when the paramecia are removed from the toxic cultures and grown for a number of generations in cultures of non‐toxic bacteria.

The toxic agent that is lethal to paramecía is probably the soluble toxin of B. pyocyaneus. The investigation shows that the agent is soluble and either thermolabile or volatile. It also shows that all deleterious substances, other than the soluble toxin, known to be produced in cultures of this bacillus, are non‐lethal to paramecia.

Hay‐infusion cultures of Bacillus enteritidis were lethal to paramecia. All attempts to develop tolerance in paramecia for the toxic agent in these cultures failed.

Under the experimental conditions that prevailed, diphtheria toxin was found to have no appreciable effect upon the division rate or death rate in three species of paramecia.
The chromosomes of the guinea‐pig
Authors: League Bessie Beakley
Published: February 2005

The spermatogenesis of five guinea‐pigs was studied. The spermatogonial chromosome number is approximately sixty‐two plus or minus two. The primary spermatocyte number is approximately thirty‐one. The spermatogonial number in the early prophase is lower than it is in later stages. This condition is due to late fragmentation of the large chromosomes found in the earlier stage. A possible sex chromosome of the X‐Y type may be identified. Its components segregate during the first maturation division.
The anatomy of the urinogenital organs of the male Myrmecobius fasciatus
Authors: Fordham Mahalah G. C.
Published: February 2005

The urinogenital organs of Myrmecobius fasciatus conform to the marsupial type in both their anatomical characters and histological details. The external genitalia indicate a close relationship with the Dasyuridae.
Binary fission in the amoeboid and flagellate phases of tetramitus rostratus (Protozoa)
Authors: Bunting Martha , Wenrich D. H.
Published: February 2005

The vesicular nucleus of this amoeboflagellate is similar in structure in both phases of its life‐cycle. It has a fairly large caryosome surrounded by a pericaryosomal area in which there are small oxyphilic pericaryosomal granules on a fine reticulum. On the inner surface of the definite caryotheca is a layer of epithecal chromatic granules.

Nuclear division is similar in both amoeba and flagellate phases. During the prophase the nucleus enlarges, and the expanded caryosome becomes resolved into basophilic and oxyphilic components and assumes either an oblong, dumb‐bell, or spindle shape. The pericaryosomal granules enlarge, shift about, and eventually become arranged in an equatorial band around the elongated caryosome. In the metaphase the equatorial plate of chromosomes appears after the inward migration of the pericaryosomal granules, accompanied by the formation of a definite intranuclear spindle, usually with polar masses, polar granules, and a centrodesmose. After the poleward migration of the daughter plates of chromosomes in the anaphase, the telophase constriction of the nuclear membrane produces two daughter nuclei with a portion of the spindle remaining outside. The epithecal layer of granules remains in place on the nuclear membrane during the entire process of mitosis. Plasmotomy normally follows mitosis, but may be delayed, giving rise to multinucleate individuals. In the flagellate the blepharoplast usually divides simultaneously with, but independently of, the nucleus. There are many divergences in the details of mitosis, but these are thought to be variations of one type of division rather than examples of different processes.
The history of the chromosomal vesicles in the segmenting egg of cryptobranchus allegheniensis
Authors: Smith Bertram G.
Published: February 2005

During the telophases each chromosome becomes inclosed in an individual sac or vesicle which, together with its contents, is called a chromosomal vesicle. The vesicular membrane is of cytoplasmic origin, but is formed under the influence of the chromosome and a droplet of karyolymph. A precise numerical correspondence between chromosomes and chromosomal vesicles has not been established, but it is evidence that most, if not all, of the chromosomal vesicles retain their individuality during the resting stage and until after the new chromosomes have been fully formed.

The transformation of the telophase chromosome into the reticulum of the resting stage and the manner in which a new chromosome is formed from a portion of this reticulum are described in detail. In the early prophases each developing chromosome is embedded in a sheath or matrix of less deeply basophilic material, which disappears before the middle prophase is reached.

The formation of chromosomal vesicles is interpreted as a device for doing more rapidly and effectively, under stress of special circumstances, the work that the nucleus must accomplish during the so‐called resting stage.
A histological description of pigment distribution in the eyes of guinea‐pigs of various genetic types
Authors: Gregory P. W.
Published: February 2005

A histological study was made in the guinea‐pig of the distribution of melanin pigment in the normal dark‐eye and in various mutant types, such as the brown type of dark‐eye (b), light and dark salmon‐eye (sm), dark red‐eye (crB), brown red‐eye (crb), albino (ca), pink‐eye (p), and pseudopink‐eye (P sm b). The genes which affect pigmentation in the eye have definite qualitative or quantitative effects on the production of melanin. Eyes of the genetic constitution ca, p, or sm possess very little pigment. But eyes which have the dominant allelomorphs of these genes, C, P, or Sm, have a large amount of pigment. The non‐yellow gene, cr, and the brown gene, b, cause the deeper retinal layer, which is normally intensely pigmented throughout its entirety, to become less pigmented. There is a corresponding reduction in the melanin in the pigmented areas of the iris and choroid. In all types of eyes with reduced pigment, such as the albino, pink‐eye, and pseudopink‐eye, pigment persists in the deeper retinal layer even when it is almost absent from other regions. Moreover, in all eyes which have less pigment than the normal type there is a decided tendency for chromatophores to be located adjacent to blood vessels. This tendency is outstanding in the iris and quite noticeable in the choroid.
The comparative anatomy of the lips and labial villi of vertebrates
Authors: Anson Barry J.
Published: February 2005

An attempt is made to define lips, and on Danforth's interpretation of homology, homologous lips are found at certain stages of development in some representatives of all classes of vertebrates. The primary lips characteristic of selachians, after the maxillary and premaxillary bones have developed within the territory of the upper lip (toadfish, cod), may disappear (trout, Spelerpes), accompanied by a forward migration of the lower jaw. The secondary lips of higher forms are first indicated in certain teleosts and amphibians. Lips vary in structure to accord with their physiological functions, whether sensory, prehensile, or adhesive. Lips of the cod are highly sensory; those of the tadpole and of grazing animals, in different ways, are notably prehensile; the lips of petromyzon and the vampire, having abundant villi, are most effectively adhesive. Therefore, the smaller villi of the lips of suckling animals are presumably for tight adhesion to the nipple. The opossum and rat, however, nurse before their lips have developed. No free macroscopic villi are found on human lips, but there is a zone of thick epithelium tending to form villi. Such a zone is shown to be a widespread feature of vertebrate lips.
The leucocytes and leucocytopoietic organs of an oligochaete, pheretima indica (Horst)
Authors: Kindred James E.
Published: February 2005

The perivisceral fluid of Pheretima indica (Horst) contains five types of leucocytes: lymphocytes, monocytes, granulocytes, lamprocytes, and linocytes. The granulocytes differentiate either from free lymphocytes, from peritoneal epithelial cells lining the leucocytopoietic organs, or from lymphocytes (hemocytoblasts) embedded in these organs. The lymphocyte is a hemocytoblast. The eosinophilic granulocyte is the most numerous of the several types of granulocytes. Morphologically and tinctorially, it resembles the eosinophil of fishes. The eosinophil granule is thought to arise either by a ripening of a basophil granule and to pass through a metachromatic phase during this process, or by being formed immediately without such a ripening process in small hemocytoblasts. The stimulus for the excessive production of eosinophils is thought to be the degree of infection of the leucocytopoietic organs by a species of the gregarine, Monocystis.

A series of segmentally arranged leucocytopoietic organs is described for the first time in the oligochaetes. These organs are essentially foldings of the septa and offer sacculations in which leucocytopoiesis may take place.

A discussion of the possible phylogeny of the hemocytopoietic organs of the invertebrates and vertebrates is given.
Reaction of certain cytoplasmic inclusions to vital dyes and their relation to mitochondria and Golgi apparatus in the flagellate Peranema trichophorum
Authors: Hall Richard P.
Published: February 2005

Two types of cytoplasmic inclusions, differing in reactions to vital dyes and to osmic fixation and impregnation have been demonstrated in Peranema trichophorum. The mitochondria are rod‐like and lie in more or less spiral rows, forming a single layer beneath the periplast. They are stained supravitally with Janus green, but not with neutral red. They may be demonstrated by staining in iron hematoxylin after Mann‐Kopsch fixation. They are also blackened in prolonged osmic impregnation, but are bleached readily with hydrogen peroxide.

The small spherical osmiophilic inclusions are scattered in distribution, although sometimes more numerous in the anterior third of the organism. These bodies are stainable supravitally with neutral red, neutral violet, and brilliant cresyl blue. They are densely blackened in osmic impregnation, and are not bleached in the usual treatment with hydrogen peroxide. They are not however, demonstrated by Mann‐Kopsch fixation and iron hematoxylin. After being stained supravitally with neutral red, these inclusions may be blackened under direct observation by exposure to osmic vapor in hanging‐drop preparations.
Seasonal cycles of the interstitial cells in the testis of the horned toad (Phrynosoma solare). Seasonal variations in the number and morphology of the interstitial cells and the volume of the interstitial tissue
Authors: Blount Raymond F.
Published: February 2005

A histological study has been made of a series of Phrynosoma testes taken at frequent intervals throughout the year. As it was important to differentiate between the amount of interstitial tissue and the number of cells, it was necessary to take into account the percentage of tissue, total testis volume and the number of cells per unit volume.

The results show a definite interstitial‐cell cycle. Volume of interstitial tissue and size of individual cells are greatest during the breeding season, but the interstitial‐cell number is then minimal. The maximal number of interstitial cells occurs after the close of the breeding season. There is, apparently, no reversion of interstitial cells to a connective‐tissue‐cell type.

The above changes are correlated with the spermatogenetic cycle and with increases in total tubule length, in tubule diameter, and in testis volume. The time in which important changes in ovarian volume occur and at which ovulation takes place is coincident with the testicular changes.

Interstitial cells have been stated to have no endocrine function for the reason that their number is at a minimum during the breeding season. If, however, interstitial tissue is responsible for sex characters and activity, the present work would indicate that it is the volume of tissue, and not the number of cells, that is important.
Intersexuality in Rana cantabrigensis
Authors: Cheng Tso‐Hsin
Published: February 2005

The specimen described presents a typical intersexual condition, in which not only the primary sex characters, but also the accessory sex organs and the secondary sex characters are of a mixed type. Both gonads are ovotestes, in which the ovarian as well as the testicular tissues are morphologically normal, but functionally underdeveloped. Stromal hyperplasia is distinct, especially so in the left gonad; it is probably a functional factor in the generative process of the spermatic tissue.

Sex transformation in the intersexual frogs may probably be initiated by an abnormality in sex differentiation or in the genetical constitution of sex, and is only subsequently influenced and modified by environmental action. Absolute dominancy of male sex in the process of sex transformation is questionable. There are indications that in frogs sex transformation may possibly occur in a female direction.
The neutral‐red reaction
Authors: Koehring Vera
Published: February 2005

A general survey of the reaction of neutral red upon a selected series of living animal organisms is made, and the rationale indicates that neutral red is an indicator of proteolytic enzyme action, whether this be intra‐ or extracellular. Cellular hydrolytic and cellular synthetic systems are thus manifested. The neutral‐red reaction also reveals the course of assimilation and secretion in organisms, the nature of fertilization, and the beginning of embryological differentiation.
The early development of Haemichromis bimaculata, with special reference to factors determining the embryonic axis
Authors: McEwen Robert S.
Published: February 2005

Haemichromis bimaculata is a tropical teleost fish which will produce eggs practically throughout the year at intervals of from three to four weeks. These eggs are of suitable size and character for embryological study, the features of special interest so far discovered being as follows: (1) The egg is oval; (2) it is attached to a substratum by its side, the blastopore being at one end; (3) the embryo always tends to develop along the side opposite that originally next to the substratum.

Results obtained by reorienting the eggs previous to cleavage, and by centrifuging them, seem to show that the relation of the embryonic axis to the egg is determined either previous to laying or very soon afterward, possibly by the relation to the substratum, and is not subsequently affected by gravity or other known factors. There may be some tendency for the first cleavage plane and the sagittal plane of the embryo to coincide, but such coincidence is not at all constant or exact.
The morphology of the amphibian endolymphatic organ
Authors: Dempster W. T.
Published: February 2005

An extensive survey of the anatomy of the endolymphatic organ (i.e., endolymphatic sac and duct) has been made on thirty‐four species of amphibians.

The histological structure is similar throughout the group; the sac being formed of cubical cells, which grade into the columnar cells of the duct. A part or the whole of the duct is formed of peculiar ‘ependyma‐like’ cells.

The organ typically arises from the sacculus, extends to the endolymphatic foramen by which it enters the endocranial cavity. Here the sac‐like expansion of the organ lies in the extradural space.

Six morphological types of endolymphatic organ may be recognized in the Amphibia.

The development of the endolymphatic organ of four of these types has been followed. The structure in each case may be considered to have reached its definitive condition at the time of metamorphosis.

The types of sac structure cannot be readily correlated with any habit of the animals possessing them.

A discussion is given of the homology, comparative morphology, and function of the organ throughout vertebrates.
A cytological study of the changes occurring in the oenocytes of Galerucella nymphaeae Linn. during the larval and pupal periods of development
Authors: Albro Helen T.
Published: February 2005

A study of the cytological changes occurring in the larval oenocytes of Galerucella nymphaeae Linn., correlating those changes with the molting cycles. Preceding each larval molt, vacuoles, apparently of nuclear origin, are found in the cytoplasm from which they are eliminated at the time of the molt. The accumulation of vacuoles is not so striking at the times of pupation and the emergence of the imago, but occurs nevertheless. Beginning with pupation or just previous to it, the larval oenocytes seemingly undergo a process of deterioration, decreasing in size and presenting a ragged appearance.

The fat‐cells are closely associated morphologically with the larval oenocytes, and it seems that there is a probable physiological relationship also, since the fat‐cells undergo a series of changes at the same time the oenocytes are exhibiting their cyclic behavior. Furthermore, it has been observed that in many instances there is a greater accumulation of vacuoles in that part of the cytoplasm of the oenocytes which is adjacent to the fat‐cells than elsewhere.
Chromosome studies. II. Synapsis in the Tettigidae, with special reference to the presynapsis split
Authors: Robertson W. R. B.
Published: February 2005

Homologous chromosomes entering parasynapsis are already split. This split evidently originates in each chromosome in the resting period prior to the last spermatogonial division. In the prophase of this division the daughter chromonemata in each halfchromosome were probably incompletely separated, but the succeeding telophase effects the completion of their separation. These processes are accompanied and suceeded by an elongation, straightening, and general paralleling of the split threads and by an elongation of the cell and its nuclear space.

Parasynapsis begins with intimate approximation of the daughter threads in each homologue and is continued by approximation of the homologues at the usual [bouquet] and [zygotene] periods. There results the [diplotene] thread, which therefore consists of four completely distinct strands, but which exhibits a [two‐strand] appearance due to parasynapsis between daughter chromonemata being further advanced than that between homologues.

The pairing process begins at the distal ends and proceeds proximally. With parasynapsis complete, the nucleus enters the [diffuse] stage On emergence, disjunction is seen to have progressed from the distal ends to near the proximal ends in each pair and the [tetrads] have taken form. In the prephase that follows each strand in a tetrad may [crimp] independently, and with the condensation and matrix (?) formation that accompany it there results the spermatocyte ‘tetrad.’
Observations on the ‘renal‐portal’ perfusion in etherized birds
Authors: Das B. K.
Published: February 2005

This investigation was made to demonstrate the direction of the current of a perfusing fluid (hence that of blood in nature) inside the so‐called [renal‐portal] vein of birds and to determine if this vein has any fine capillaries in the kidney substance. A domesticated male duck was anaesthetized with ether, and a warm saline (mixed with a little urea and urine) was passed through the aorta. The [renal‐portal] vein was also perfused with the same fluid through the left internal iliac vein. At first the kidneys actively secreted semisolid urine, but gradually the strength of the latter varied from a milky to a watery fluid.

Later, a warm carmine solution was perfused through the left internal iliac vein, and the path of the dye could be easily traced along the whole length of the left renal afferent (left [renal‐portal] vein) and its final exit through the postcaval vein. The posterior lobe of the left kidney was partially tinged with red, probably due to diffusion, since the kidney substance should have taken a uniform red hue if there was any definite capillary system. The coccygeomesenteric vein contained no dye.

These results (coupled with actual caliber measurements of the two [renal‐portal] veins in duck and pigeon examined, the calibers of these veins increasing gradually posteroanteriorly) indicate that: 1) blood flows anteriorly in the [renal‐portal] vein; 2) this vein does not break up into capillaries in the kidney substance, but receives larger affluent veins; 3) there is no [renal‐portal] system in birds; 4) the urine secreted by birds is always semisolid.
Blood formation in the african lungfish, under normal conditions and under conditions of prolonged estivation and recovery
Authors: Jordan H. E. , Speidel C. C.
Published: February 2005

The blood cells of the African lungfish, Protopterus ethiopicus, are very large and resemble those of urodeles. Leucocytes are especially plentiful and rich in variety, including eosinophils, special eosinophils, [meta‐eosinophils] with atypical granules, monocytes, thrombocytes, lymphocytes, and basophils.

The chief hemocytopoietic organs are the spleen, intestine, and kidneys. The lungfish spleen, embedded in the wall of the stomach, represents an intermediate phylogenetic stage between the disperse intra‐enteral type of the hagfish and the compact extra‐enteral type of other vertebrates.

Erythrocytes are formed in the spleen pulp, granulocytes in the granulocytopoietic organ of the intestine and in the capsules of kidneys, gonads, and spleen. Thrombocytes and monocytes are differentiated in the spleen and general circulation. Basophils arise in the spleen and intestine. Lymphoid cells of all types arise in the spleen. Evidence is presented bearing upon the hemocytopoietic capacity of the various types. Cells with [Russell bodies] also occur in the spleen.

In lungfishes subjected to long periods of dry estivation, erythrocytopoiesis practically ceases. Granulocytes, however, appear to play an important rǒle, possibly in fat metabolism. The large variety of meta‐eosinophils, a unique feature of the lungfish, appears to be associated with the habit of estivation.

Recovery from estivation may show numerous amitoses of erythrocytes in the general circulation. Other cells which divide in this manner are young thrombocytes, granulocytes, monocytes, and lymphoid hemoblasts.
Recovery from immersion in water. An index of metabolism and the condition of the gonads in Drosophila melanogaster Meigen and Popillia japonica Newm.
Authors: Eddy Milton Walker
Published: February 2005

In some insects the selection of individuals which recover in equal periods of time from immersion in water may be used to obtain material of approximately uniform physiological state; Drosophila melanogaster, Meigen, was found to have a mean of recovery for the males 0.97 ± 0.542 minute later than the females, which would indicate a lower metabolic rate for the males. The Japanese beetle, Popillia japonica Newm., was found to have a mean of recovery from immersion in water of both sexes the same in August, while in September the males were retarded by 8.1 as compared with females. This would indicate that the males have and equal me abolic rate in August with the females and a lower rate in September. Carbon dioxide, hydrogen, and nitrogen produce in the flies a condition of asphyxiation similar to immersion in water. [Vestigial] flies recover from immersion in water in a fashion similar to ‘wild’ flies.

The recovery periods from immersion in water in the flies can be used to group individuals into those possessing approximately equal egg‐laying capacities and to isolate spent individuals from others still capable of laying eggs. Yeast appears to be more of a stimulant to egg laying than it is to larval growth. Groups of flies which were fed yeast were found to average 71 per cent increase in egg laying over groups of flies that were not fed yeast. The O2 consumption of the groups of flies actively laying eggs, as contrasted with the groups which were not so active, was found in the former to be 32.9 per cent greater.
History of the germ cells in Sphaerium striatinum (Lam.)
Authors: Woods Farris H.
Published: February 2005

Study of living and sectioned material throughout the life cycle shows the germ‐cell history from fertilized egg to sexual maturity. This can be divided into the following five periods with definite limits: Original appearance during cleavage, period of inactivity, period of multiplication, maturation, and fertilization. Primordial germ cells of characteristic structure can be recognized just before gastrulation, when there is one large germ cell in the mass of mesoderm on either side of the blastocoel. After one division in each of these two cells, the four daughter cells remain inactive, while the remainder of the mesoderm differentiates, until division is resumed in the developing gonad. An indefinite number of gametes is produced. All are direct descendants of the two original primordial germ cells. Transformation of somatic cells into germ cells does not occur nor do germ cells become somatic cells. Cell lineage shows the two primordial germ cells to be derived from the third division of the paired mesoderm cells which have arisen by an equal division of the fourth micromere produced by cell D of the four‐cell stage. Details of meiosis have not been ascertained, because of the small size of the chromosomes, their large number, and the difficulty of fixation. Nothing forecasts which primordial germ cells will become ova and which spermatozoa.
Cytoplasmic structures in binucleate opalinids, with special reference to the Golgi apparatus
Authors: Richardson K. C. , Horning E. S.
Published: February 2005

Three types of cell inclusions are demonstrated within the general protoplasm of the binucleated Protoplina, parasites of Hyla aurea. These are considered to represent mitochondria, together with associated, synthesized vegetative granules and Golgi bodies, as evidenced by their behavior, morphology, and staining reactions.

The Golgi material is shown to consist of irregularly twisted rods and granules scattered at random in the cytoplasm, but possessing a very distinctive morphology and reaction to different techniques when compared with the mitochondria. No relationship could be detected between these vegetative structures and the cilia, as has been previously described.

These observations have also been extended to a similar study of the cytoplasmic organs of Nyctotherus cordiformis, and it has been possible to demonstrate Golgi bodies of a similar appearance within this organism as well as to show again the nature of the basal granules and their relationship to the cilia.

The procedure of identifying the mitochondria elements with great care is recommended as a preliminary means of studying the Golgi apparatus of Protozoa, particularly where osmication techniques are used exclusively.
The anatomy of diplodinium medium
Authors: Rees Charles W.
Published: February 2005

In this paper evidence is given in support of the author's statements (Rees, '30) that in ciliates in the genus Diplodinium a neuromotor apparatus, as described and figured by Sharp ('14), could not be differentiated. For the study of minute anatomy ciliates were cut into serial sections 3 μ thick. The body which in D. medium appeared to correspond to the motorium of D. ecaudatum was shown to be a fold of the middle layer of ectoplasm. Fibers, described and figured by Sharp as connecting the motorium to the organelles of locomotion and of food taking and to a ring about the esophagus, could not be differentiated. Other fibers which Sharp designated as opercular were shown to be part of a fibrillar complex extending throughout the middle layer and the inner boundary layer of ectoplasm. The walls of the esophagus were shown to be formed by the fused middle and inner layers of the ectoplasm. The esophageal fibers therefore belong also to the above‐mentioned fibrillar complex. In D. medium a system of esophageal membranelles was differentiated, described, and figured. The ciliary systems of Paramaecium ecaudatum and of Diplodinium medium were shown to be strikingly similar. The principle of descent from a common ancestor adequately explains the above similarity, but is out of harmony with the discrepancies between Sharp's account of D. ecaudatum and this account of D. medium.
A detailed study of the endoderm of hydra
Authors: McConnell Carl H.
Published: February 2005

The flagella of the endodermal cells of hydra have their origin in the form of a cytoplasmic spherule which appears on the cell membrane just above the blepharoplast. This spherule moves outward, and in doing so forms a small cylinder, which, in time, flattens down into a ribbon‐like flagellum, the edge of which is slightly thickened. Endodermal cells were found to bear from one to five of these flagella. Dissociated endodermal cells become amoeboid and are able to move about quite freely, taking up particles of food with pseudopods; these cells are also able to elaborate flagella. In the normal well‐fed hydra the endodermal cells are found to fragment endogenously; these endogenous fragments pass to the tentacles and other outlying regions, where they are taken up by the endo‐epithelio cells lining these regions. The endoderm is frequently thrown into villi of quite large size: these villi, when studied over a period of days, are found to deteriorate; the cells which composed them wander to the tentacles, buds, and basal regions by means of their flagella and amoeboid movement, where they deteriorate, the cell particles being taken up by the epithelio cells lining these areas.
A comparative study of the chromosomes of rodents
Authors: Cross James Cecil
Published: February 2005

A comparative study has been made of fifteen species and subspecies of rodents to determine the range in number and variation in morphology of their chromosomes. The number range is between 40 and 86±, with an average number for known species of 52. In the family of Cricetidae there is little variation in chromosome number and a general similarity of the chromosomes. In the Muridae the range for known species is 40 to 42, but the chromosome morphology even of subspecies may be quite different. In Sciuridae a range of 48 to 62 has been found in different species. The greatest range in number is found in the Heteromyidae, 44 and 86± chromosomes having been found in two species. It is concluded that the stem number for rodents is close to 48 and that fragmentation and fusion account for variation in numbers, and these affect the morphology of the chromosomes. The evidence also indicates that variations in morphology are due to translocations and inversions, and possibly deletions accompanied by translocations.
The distribution of sperm‐forming materials in scorpions
Authors: Wilson Edmund B.
Published: February 2005

There are in scorpions two sharply contrasting types in respect to the mode of distribution of the chondriosomes to the sperm cells. In one of these the chondriosomes, spheroidal in form and nearly definite in number, are sorted out whole without division during the spermatocyte divisions, their number being thus reduced successively to one‐half and one‐fourth. This type occurs in Opisthacanthus, Hadrurus, Vejovis, Euscorpius, and Palamnaeus. In the other, as yet known only in Centrurus, all the chondriosomes fuse during the spermatocyte growth period to form a single ring‐shaped body; and this, during the two ensuing mitoses, is accurately divided into two, four, and eight equal parts, of which each spermatid receives two. In both types alike the chondrioma is thus distributed very nearly equally to the sperm cells, but by widely contrasting processes; and in both types the spermatid chondriosomes are drawn out to form the sheath of the axial filament in the sperm tail. In Opisthacanthus there are indications of a definite process of dictyokinesis during the spermatocyte divisions.

These facts are discussed in the light of the general history of the chondriosomes in other animals, with especial reference to more general problems of cell division. The present vagueness and uncertainty of our knowledge of cell division and differentiation are emphasized.
Some cytoplasmic structures in the male reproductive cells of a pseudoscorpion (Chelanops corticis)
Authors: Nester Henry George
Published: February 2005

The chondriosomes of the germinal epithelium are vesicular, whereas the Golgi material takes three forms. The aggregation of chondriosomes about the Golgi cap, located on the nucleus, suggests a chemical interchange between these in the growth period. They become cylindrical as the Golgi cap moves from the nucleus and becomes spherical. It is at this time joined by other Golgi material. The entire aggregation is dispersed previous to the maturation divisions, where the inclusions studied are only approximately equally divided, in contrast to conditions in the true scorpion, Centrurus exilicauda. Golgi granules on chondriosomal surfaces in the spermatid again suggest chemical interchange. The later changes of chondriosome vesicles to discs, and back to spheres, may be means of regulating chemical reaction. A close relation between chondriosomes and Golgi material is indicated by various bodies, of Golgi origin, within the former in the spermatid. A thick thread finally originates from among the chondriosomes of the elongated sperm. Spiral threads surrounding the elongating nucleus arise from reunited Golgi material, a derivative of this substance not previously recorded. The acrosome, also of Golgi origin, undergoes several changes in shape and shows several parts. The elongated nucleus, spiral thread of Golgi origin, acrosome, chondriosomal thread, and unusually long axial filament become coiled and encysted in an oval mature sperm capsule. In the female duct the sperm uncoils.
A comparison between the ultraviolet microscopy and the Feulgen staining of certain cells
Authors: Wyckoff Ralph W. G. , Ebeling Albert H. , Ter Louw Adrian L.
Published: February 2005

This paper describes ultraviolet (λ = 2750 A) photomicrographs of resting and dividing chicken macrophages and fibroblasts and of erythrocytes and lymphocytes. The structures found in these photographs are compared with the ones brought out in fixed material by Feulgen staining and found to be essentially similar in appearance. A preliminary series of ultraviolet pictures is also shown of a single fibroblast passing through several of its stages of division.
The architecture of the parietal cells of the salivary glands of the grasshopper, with special reference to the intracellular canaliculi, Golgi bodies, and mitochondria
Authors: Beams H. W. , King Robert L.
Published: February 2005

The parietal cells of the salivary glands of the grasshopper are large and roughly spherical or sometimes pyramidal in form, scattered for the most part singly among the zymogenic cells of the lobules. They possess a magnificent system of intracellular canaliculi into which their secretions are directly emptied and conveyed to the exterior of the cell. These intracellular canaliculi are strikingly impregnated with osmic‐acid methods (Nassonov, Mann‐Kopsch) in a manner comparable to the contractile vacuole of Paramecium as described by Nassonov. However, in addition to the impregnated system of intracellular canaliculi, Golgi bodies are found evenly distributed throughout the cell in the form of crescents, semicircles, or ring‐like structures typical of insect tissue.

Inasmuch as a direct homology between the intracellular canaliculi and the contractile vacuole of Paramecium, both from the point of view of morphology and physiology, seems justified, we question the inference drawn by Nassonov that the impregnated walls of the contractile vacuole in Paramecium actually represent Golgi material. Deduction is made from these and previous studies that the magnificent network of ‘vacuome‐Golgi apparatus’ described by Parat and Painlevé ('24) in the salivary glands of Chironomus larvae is nothing more or less than intracellular secretory canaliculi.

Mitochondria in the parietal cells are abundant in the characteristic form of short rods and filaments. No evidence of a direct transformation of mitochondria into Golgi bodies. as held by Parat, was observed. Golgi bodies and mitochondria show no marked topographical relationship to the intracellular secretory canaliculi.
Coordination of ciliary movement. I. Methods of study and the relation of ciliary coordination to ciliary inhibition
Authors: Lucas Alfred M.
Published: February 2005

A simply constructed apparatus, which includes a cinema camera, is described for the recording of ciliary movements. From data for Modiolus demissus obtained by this method, it is concluded that the coordinating impulse is a propagated impulse which regulates the temporal and spatial relationships of ciliary contractility, that this impulse has to a certain degree a determinant effect upon ciliary inhibitory influences so that the area rendered inactive is a multiple of the ciliary wave length, that the coordinating impulse is transmissible through cells bearing quiescent cilia, and that it may act as a stimulus of sufficient strength actually to cause quiescent cilia to become active.
A topographical and cytological study of the sympathetic nervous components of the suprarenal of the chick embryo
Authors: Brauer Alfred
Published: February 2005

A study was made of the development of the suprarenal gland of the chick with reference to the following points: 1) Topographical relationship of the sympathetic cell masses to the cortical cords, and to the sympathetic nervous system. 2) Cytological differentiation of the sympathetic cells.

The migrating indifferent sympathetic cells, although becoming generally distributed over the medial surface of the cortical ridge, form a series of more prominent aggregations at certain definite loci. These aggregations are the rudiments of two longitudinal ganglionic chains, which develop from the sixth to the seventh day. Around and between the ganglionic rudiments the indifferent cell groups become penetrated by sympathetic fibers from the ganglionic rudiments as well as by fibers of sympathoblasts which develop from indifferent cells of the sympathetic‐chromaffine complex. At the same time multipolar sympathetic cells lying between the cortical cords and processes to the tracts developing between the ganglia on the surface of the cortical ridge.

Differentiation of ‘chromaffine cells’ from indifferent cells of the aggregations begins during the eighth day, after a profuse innervation of the rudiments has been established. Differentiation is evidenced by the appearance of cytoplasmic granules, and by the appearance of the ‘chromaffine reaction.’ The possible bearing of the innervation of the indifferent cell aggregations upon their differentiation and upon their penetration of the cortical bodies is discussed.
DIE BILDUNG DER ERYTHROCYTEN IM KERNE DER PLASMOCYTEN; DER HÄMOGLOBINSCHWUND IM BLUTKREISLAUFE MIT DER PIGMENTMETAMORPHOSE UND OHNE DERSELBEN UND DIE BESONDERE ELIMINIERUNGSART DER CHROMATINSUBSTANZ AUS DER ZELLE IM BLUTE DES BATRACHOSEPS ATTENUATUS ESCH.
Authors: Komocki Witold
Published: February 2005

In the blood of Batrachoseps one part of the erythrocytes is formed inside the nucleus of plasmocytes as a result of the metamorphosis of chromatin substance. When erythrocytes are completely formed, they separate themselves from the plasmocytes.

Disappearance of the hemoglobin of erythrocytes with pigment metamorphosis is visible in the drawings.

When the disappearance of hemoglobin with pigment metamorphosis takes place, the color of the hemoglobin cytoplasm frequently becomes very pale. The hemoglobin cytoplasm may vanish also without pigment metamorphosis in such a way that the whole cell (nucleus and cytoplasm) swells, and the cytoplasm becomes paler, and finally only a pale shadow remains which is rather difficult to distinguish. The author has noticed in the blood of Batrachoseps, besides extrusion of small nuclei from the erythrocytes, also a particular way in which chromatin substance is eliminated from the cell. While the cell and the nucleus become pear‐shaped, the nucleus moves toward the periphery, touching the surface of the cell with its funnel‐shaped narrow side. From this narrow side the chromatin substance flows out in the form of a band stained red, according to Romanowsky.
The effects of X‐rays on anterior regeneration in tubifex tubifex
Authors: Stone Raymond G.
Published: February 2005

Observations of earlier workers concerning the limited region from which anterior regeneration will occur in Tubifex and the reduced number of segments formed were confirmed in control worms used in these experiments. Only three anterior segments are replaced when as many as twelve are removed. Regeneration is completed within 18 days.

Removal of anterior segments from worms that have received 9000 (r) units exposure to x‐rays is not followed by regeneration. The wound heals rapidly and worms have been kept in laboratory 70 days without further change. Longitudinal sect ons of injured ends show that the epidermis and muscle layers extend across the wound surface to completely close the body cavity. The intestine retracts slightly and heals to form a blind tube. No mitotic figures appear in cells of this region and there is no evidence of regeneration.

In control worms material for formation of the cerebral ganglia and new epidermis arises by proliferation of epidermal cells. The new pharynx arises from the region of the old intestine adjacent to the wound surface. The muscle layers of the body wall and pharynx in new segments are apparently formed by migration of cells from the old muscle elements about the margin of the wound area. No neoblasts were observed in anterior migration or in the process of formation upon adjacent septa in any of the worms.
Homology of the paired fins in fishes
Authors: Howell A. Brazier
Published: February 2005

Recent and fossil fishes may be divided into groups having both pectoral and pelvic fins, pectorals only, pelvics only, or with a second pair of fins located anteriorly and seemingly not homologous with pelvics. In some groups the pelvics are located near the cloaca, with an extensive hiatus between the pectoral and pelvic neuromeres; other groups are of an intermediate character, while in a third group the second pair of fins appears to have no relationship to the pelvics. The character of the innervation indicates that they could hardly have been derived from the latter, and the few nerves, consecutive with the brachial plexus, which supply them suggest origin from the posterior elements of the dermal series, the anterior of which became the pectoral fins. Instances even occur (Polynemus) in which a third pair of appendages has been derived from the original pectoral complex.
The development of the external form of the guinea‐pig (cavia cobaya) between the ages of 21 days and 35 days of gestation
Authors: Harman Mary T. , Dobrovolny Marjorie Prickett
Published: February 2005

The authors are preparing a table for the normal developments of the guinea‐pig. This paper deals with the external form and the development of the external characteristics of guinea‐pigs between 21 days and 35 days, copulation age. About one hundred embryos were used from thirty‐six litters.

Length and weight are good criteria for determining age, although there is some variation. The flexures, the disappearance of the tail, the development of hair follicles at specific locations, the degree of development of the mouth and external ear are better criteria for the determination of age.

At 27 days there is a sudden increase in both weight and length. This increase is rather uniform from this period until the end of 35 days. At this time the embryo has the appearance of a newborn guinea‐pig.
The development of the carp, cyprinus carpio. II. The development of the liver‐pancreas, the Islands of langerhans, and the spleen
Authors: Smallwood W. M. , Derrickson Mary Burton
Published: February 2005

The first stage in the formation of the liver is two ventrolateral evaginations of the mid‐gut at the time of hatching. From the undifferentiated cells branching from the liver duct the pancreas cells arise, but do not assume adult character until the carp is about 41 mm. long.

The islet makes its first appearance in the region of the pancreatic duct at the 8‐mm. stage and shows no transitional stages. In the mesenchyme itissue dorsal to the intestine the spleen arises, and is finally completely surrounded by the liver‐pancreas.
The development of the sino‐atrial region of the chick heart
Authors: Quiring D. P.
Published: February 2005

The development of the interatrial septum and the relation of the sinus venosus and sino‐atrial valves to the interatrial septum was followed in chick hearts ranging from 50 hours of incubation to the adult. The following singificant facts were established. The interatrial septum first appears at about 50 to 55 hours of incubation. It fuses with the endocardial cushions of the atrio‐ventricular canal, typically in the last quarter of the fifth day. Secondary perforations appear in the septum at the time of closure of the interatrial foramen primum. These are retained until hatching, although they may persist in the adult heart. The sinus venosus, a sinus septum, and the sino‐atrial valves are retained as definite structures in the adult fowl heart. The pulmonary vein and the left precava as they enter the heart form a prominent addition to the inter‐atrial septum proper which I have designated as the pars cavo‐pulmonalis. The pulmonary orifice in the left atrium is provided with an extensive flap‐like valve. A prominent limbus of Vieussens is present in the right atrium. A well‐developed median muscular arch overlies the interatrial septum and a pair of lateral muoscular arches extend over the atria. Their position would seem to be significant in the closing septal perforations during atrial systole.