1) The nature of the submaxillary gland and appearance of germ cells in the ovaries after ablation of the submaxillary gland were studied in guinea pigs. 2) The formation of antrum in the follicles and aberrant ovarian folliclies were found in the females after submaxillariectomy. These changes of ovarian follicles which occurred in the present experiments may be due to changes in the estrogen as the result of the submaxillariectomy. 3) The correlated action between the ovary and the submaxillary gland in order to maintain the normal condition of these organs was confirmed as in the case of submaxillariectomized males. 4) The occurrence of binuclear ova was observed with rather high frequency in submaxillariectomized females, and these ova undergo maturation division as in case of uninuclear follicles. Their origin may be in the fusion of ooplasm of primodial ova. 5) In the dissection of pregnant females after submaxillariectomy, the resorbing embryos and a pair of embryos with a common placenta on one implantation site were found, and abnormal implantation embryos may be accounted for by the occurrence of binuclear ova. 6) The occurrence of polyovular follicles was also observed in submaxillariectomized females, and in the biovular follicles maturation may occur. The origin of biovular follicles is thought to be in the massing of primodial ova. 7) Three cases of an excessive number of implantation embryos as compared with that of corpora lutea were found in the females produced by the mating of submaxillariectomized females with normal males, and these cases may be accounted for by the occurrence of biovular follicles. 8) In the breeding results only one abnormal specimen has been obtained in the submaxillariectomized progeny, and high frequency of the female in the sex-ratio was found in the cross of the submaxillariectomized females with the normal males.
The megasporocytes of Lilium constitute excellent material for the study of nucleoli since they are quite large, are not so masked by the chromatin at most stages as are the microsporocytic nucleoli, and the stages are lengthened in time making it easier to get a completely graduated series for study. Two types of extrusions emerge from the nucleoli. A homogeneous substance is extruded as the megasporocyte begins to elongate and a small globular body is extruded in early prophase I. The latter extrusion occurs concurrently with, or immediately before, a deep invagination is formed in the nucleolus.
1. Cytological studies on six different species and varieties of the genus Gardenia have been performed. All the individuals have been found to be characterized by 2n=22 chromosomes. The species are:- i) Gardenia jasminoides Ellis ii) G. jasminoides Ellis var. stanleyana iii) G. jasminoides Ellis var. fortuniana iv) G. tubifera wall. v) G. lucida Roxb. vi) G. kirkii 2. Detailed karyotype analysis of all these species have been carried out and each species has been shown to have a distinct karyotype of its own. This shows that changes in chromosome morphology have been an associated feature of their evolution. 3. Chromosomes are mostly medium in size with generally median to submedian primary constrictions. Number of chromosomes with secondary constrictions have been found to vary from four to ten. In G. jasminoides, a pair of chromosomes with supernumerary constrictions has also been recorded. 4. Nuclei with altered chromosome complements have been noted in the tissue of the same species and their role in evolution has been discussed. It has been suggested that these altered chromosome complements can give rise to daughter shoots with different genomic constitution maintained in otherwise normal numbers. 5. Numerical variations of chromosome number in the somatic tissue have also been detected. In absence of any species with different chromosome number, numerical variations seem to play no important role in speciation of this genus.
1. The degree of differentiation attained after chilling varies from one H-segment to another in Trillium, both between and within the species. These can be grouped into four degrees: 1° Slight (e.g. T. stylosum) 2° Moderate (e.g. most Trillium segments) 3° HIGH (e.g. Paris polyphylla) 4° Extreme (e.g. T. undulatum and Japanese species) 2. H-segments lose their differential appearance when chilled chromosomes are blocked at metaphase and returned to normal temperatures. This would seem to be due to a synthesis of DNA by H-segments, which are regarded as being retained in an early prophase condition. There is evidence that all H-segments from metaphase to late anaphase are capable of such synthesis. 3. Differential reactivity in polyploid cells and plants is identical with that in its diploid counter-part. 4. Chemical treatment of Trillium chromosomes has failed to reveal H-segments. This might be due to the chemical treatments being nonspecific for heterochromatin. All the chemical methods suggested in the literature seem to be variable and therefore unreliable in their results.
1. The normal complement of the Chinese hamster consists of 11 pairs of readily distinguishable chromosome types. 2. The sex bivalent of the Chinese hamster is the third largest in the complement. It resembles the J-shaped “isomorphic” Chromosome pair VIII. Earlier selections by Matthey and Pontecorvo, involving heteromorphism and or the largest metacentrics as sex elements, are considered incorrect on the basis of present experimental data. 3. Variation in the length of Chromosome I is due to mechanical stretching, leaving the impression of heteromorphism of homologues. 4. Reciprocal translocations are readily identified in offspring sired by x-irradiated males. The presence of a normal appearing sex bivalent with a ring or chain of four configuration, involving Matthey's “X” chromosome, support the writer's views that the largest metacentric pair is purely autosomal. 5. Experimental proof of the actual sex chromosomes remains to be demonstrated.
In the peculiar type of spermateleosis briefly described in 10 stages, the spermatid nucleus progressively elongates and is finally transformed directly into the mature ‘all head’ spermatozoon. A cytoplasmic ‘tail’, which appeared in the early spermatid and grew to a considerable length, was later discarded. No nuclear material was ever observed in the ‘tail’ and all the cytoplasm of the spermatid was lost except that which later formed the delicate membrane of the mature spermatozoon and the short tail remnant.
1. Histological structure of acontium of Diadumene luciae was studied by means of light-microscopical as well as electron-microscopical examinations. Certain indications were obtained that the whole surface of acontium was covered by a thin, continuous, uniformly ciliated sheet of protoplasm, which also separated the distal end of the cnidae from the exterior. It was very probable that the cnidae were situated in vacuole-like cavities among the epithelium, without any cytoplasmic coat such as to be called “cnidoblast”. 2. Peculiar refractile bodies of varying forms such as could be assumed as developmental stages of cnida were abundantly found in the acontia, which were in the course of regenerating either themselves or their cnidae. Evidence obtained from their study also pointed to the view that the cnidoblast had already been degenerated in the full-grown cnidae. 3. Remarks are given of some further findings as to structural elements of acontia and of cnidae, including the peculiar globular bodies, which were normally found within the acontia and were suggested as possible precursors of cnidae. Most of the morphological findings included in the present note, as well as some of the points of view attained, may be summarized in diagram form as shown in Fig. 7.
1. The fine structure of the phragmoplast, that of the cell plate, and its formation in meiosis has been examined by means of the electron microscope in pollen mother cells of Lilium lancifolium fixed with CdC12 alcohol solution. 2. The barrel-shaped phragmoplast is consisted of innumerable parallel fibrils lying vertically to its equatorial plane, and of the fluid substances with lower density to the electron beam, which fill up the interfibrillar space. 3. The cell plate appears from its initiation as two parallel layers composed of unit fibrils which are different from those of the phragmoplast. The unit fibrils of the cell plate lie crossing vertically crosswise to the unit fibrils of the phragmoplast. 4. The cell plate develops centrifugally in the phragmoplast along its equatorial plane. 5. After the cell plate reaches the mother cell wall, cell-wall forming substances from this mother cell wall are diffused into the space between the two lamellae thus making one cell plate. The hardening of the daughter cell wall develops centripetally. The author wishes to express his appreciation to Professor B. Wada for his encouragement and suggestion. The author is also indebted to Dr. N. Tanaka and Mr. S. Sakata for criticism and technical help in carrying out this work. This work was supported in part by a grant from the Science Research Fund, Ministry of Education, and in part by a research grant from the Fuju-Kai Research Encouragement Fund.
1. Effects of proteins on the Feulgen reaction in vitro were examined. 2. The absorption maxima of colors developed with Na·DNA-protein mixtures were determined. The results of the experiment show that thymus histone and sperm protamine shift the maximum towards the longer wavelength whereas gelatin, casein and albumin do not shift. 3. Progression of the color development against time in the presence of histone·sulfate at pH 1.16, 2.28 and 3.68 was compared with those of Na·DNA alone. 4. Relation between concentrations of the proteins contained in DNA solution and color intensities was investigated. 5. Effects of pH and proteins on the color intensities were investigated.
1) In der vorliegenden Abhandlung wurden die Chromosomen von Takakia lepidozioides untersucht. Die Chromosomenzahl dieser Art ist n=4 und der Karyotypus K=V(H)+V+J+J(h). 2) Die Chromosomenzahl n=4 von Takakia lepidozioides ist eine neu gefundene, niedrigste Grundzahl der Chromosomen der Bryophyten. 3) Die Chromosomen der bisherigen Arten der drei Klassen der Bryophytes (Hepaticae, Anthocerotae und Musci) müssen polyploide Zustände sein. 4) Die sekundären Grundzahlen der Chromosomen der bisherigen drei Klassen von Bryophyten sind n=6 und 8: bei der Anthocerotae ist es n=6, bei der Hepaticae n=8 und bei der Musci n=6 und 8. 5) Die bisher gefundenen verschiedenen Chromosomensätze der drei Klassen von Bryophyten müssen zunächst vom 2V+2J-Satze infolge seiner verschiedenen Grade der Verdoppelung einerseits, infolge der Differenzierung vom H und h anderseits entstanden sein. Und dann müssen in diesen polyploiden Zuständen noch Vermehrung oder Verminderung einiger Chromosomen, besonders Verschwinden eines H oder h, ferner oder dieser beiden, vorgekommen sein.