[in Japanese]

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The triploid hybrid employed in this study has arisen from the cross between Celosia argentea L. (n=36, Fig. 2) _??_ and C. cristata L. (n=18, Fig. 1) _??_.
At the earlier stage of the heterotypic metaphase in P. M. C., all chromosome elements are scattered throughout the cell (Fig. 3). As the stage draws near to the metaphase, bivalents move toward the metaphase plate, and univalents have a weak tendency to move toward the plate (Fig. 4). At the metaphase all bivalents arrange on the metaphase plate and some univalents are present in the metaphase plate with bivalents, but most of the univalents are found at some distance from plate (Fig. 5). In this stage, 18 univalents are often counted in a side view, but it is usual that the number of univalents does not reach expected number. At the polar view of metaphase 36 chromosome elements are counted, but univalents are not distinguished from bivalents (Fig. 6). At the anaphase all univalents are distributed at random to the opposite poles together with the divided halves of bivalents (Figs. 7-9). The univalents have no longitudinal splitting in this stage.
Chromosomes lagging behind in the anaphase are frequently observed in the interkinesis (Fig. 11). These lagging chromosomes either form a microcyte in the tetrad formation (Fig. 16), or are lost in the cytoplasm.
At the metaphase of the second division all dyad chromosomes arrange themselves in strikingly regular fashion in each of the two daughter nuclear plates (Fig. 12). At the polar view of this stage 27 dyad chromosomes are often found in both daughter cells (Fig. 13). Chromosomes lagging in the first division are also clearly found in the second division (Fig. 14). In the anaphase, chromosomes farming the second division plate divide longitudinally and pass to the opposite poles (Fig. 15).
The chromosome behavior during meiosis of the triploid Celosia hybrid is very markedly similar to that which takes place in the Drosera hybrid (ROSENBERG, 1909).
The F₁ hybrid of C. argentea × cristata contained 54 chromosomes in diploid number, this being the sum of the haploid number in both parents, which had, respectively, n=36 and 18. In the F₁ plant, the chromosomes conjugate in such a manner that the 18 C. cristata chromosomes united with 18 of those from C. argentea, the remaining 18 of the latter being left as unpaired chromosomes. 18 bivalents divide in the normal way throughout both divisions. But 18 univalents distribute to the opposite poles at random without longitudinal splitting in the first division, and they divide longitudinally in the second division.

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[in Japanese]

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1. The inheritance of seed-coat colour in the water melon (Citrullus vulgaris SCHRAD.) is preliminarily reported in this paper.

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1) The original fatuoids used in this work were supplied by Dr. C. L. HUSKINS, who had already studied them.
2) Heterozygous fatuoids from three strains, H58, H20 and H93 segregated in the following generation normals, hetero- and homozygous fatuoids in a 1:2:1 ratio. The genetic results confirmed practically HUSKINS' observations.
3) Many segregates from each phenotype were cytologically studied. In all of them except 4, normal 21 bivalents were generally counted at the heterotypic metaphase in PMC. On the other hand, uni- tri- and tetravalent chromosomes were observed in a few PMC from some of these plants. The statistical counts of their occurrence are shown in Tables 2-4. From these results we can see that meiotic abnormalities occur independently of the phenotypic character of the grain, and appear to be not directly transmitted from generation to generation. The chromosome irregularities may be caused mainly by the lack of cytological equilibrium and by the polyploidy in Avena.
4) There were found to be 5 segregates with 41 chromosomes that arose in each of the phenotypes. They were probably produced through meiotic irregularities in the parent plants.
5) From them 2 heterozygous fatuoids, H58-12 and H20-35, segregated dwarf homozygous fatuoids, heterozygotes and normals in a ratio of ca. 1:1.5:0.1. The progenies from H58-12 were extensively studied. The dwarf homozygous fatuoids had 40 somatic chromosomes, but the formation of bivalents was much reduced, 0-10II, being counted so far observed. Therefore they were completely sterile. A few of low fertile homozygous fatuoids were found. Their chromosome combination might be 20II+fc1I Heterozygous fatuoids had 20II+1I. Their fertility varied widely, probably owing to the external conditions (Tables 7 and 8). Normal segregates appeared to be quite normal in the cytological and morphological features as well as in fertility. The abnormal segregation ratio is discussed with special reference to the cytological behavior.
6) The 3 other plants with 41 chromosomes lacked different chromosomes, which do not bear factors for the fatuoid and cultivated type of the grain characters.
7) Three main hypotheses on the origin of fatuoids are discussed from the genetic and cytological points of view.
8) Basing on the genetic and cytological behavior fatuoids are classified into two main groups. The first series contains fatuoids produced by the mutation of a gene complex in the c-chromosome. The common fatuoid belongs to this class. Fatuoids of the second series arose through chromosome aberrations. Owing to the deficiency of a whole chromosome the meiotic and genetic features are very abnormal.

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1. The self-pollination of female intersexual hemps was repeated for several generation.
2. No male plants appeared in their progeny.
3. The frequency of the production of female intersexes increased generation after generation until not a single female plant appeared.
4. The gradual decrease in germinating percentage was very remarkable.
5. From these facts it is probable to say that the intersexuality is influenced not only by environmental conditions but by genetic factors.

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1. From the seed obtained from selfing of intersexes in Spinacia oleracea and Melandrium ruburum, there grew only females and intersexes but none of males.
2. These facts show that the intersexes thus treated have female-like constitution in their genetic elements

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