Intra- and interspecific hybrids were easily obtained from crosses among two races (C. No. 1 and C. No. 3) of C. colocynthis Schrad. and a variety (V. No. 1) of C. vulgaris Schrad..
Chromosome behavior of the three parental races was normal throughout the course of their meiotic divisions. Chromosome conjugations at metaphase I in PMC's of the three hybrids showed 11 bivlaents in about 50% of the cells. The remaining cells showed irregular chromosome associations such as multivalents, mostly trivalents, and univalents. The frequency of the cells with multivalent associations differs among the three hybrids (Fig. 1 and Table 2). Pollen fertility was found to be approximately 50% in all of them (Table 3 and Fig. 3).
Morphological characters of the three hybrids were compared with those of their parents (Table 4, Figs. 4, 5 & 6). C. colocynthis was dominant over C. vulgaris in stripe pattern of exocarp and taste and color of flesh. On the contrary, C. vulgaris was dominant over C. colocynthis in seed and exocarp color.
Although C. No. 1 and C. No. 3 belong to the same species they differ in many morphological characters. C. No. 3 was dominant over C. No. 1 in color and stripe pattern of the exocarp. On the contrary, C. No. 1 was dominant over C. No. 3 in seed color.
Leaves of the three hybrids are intermediate in shape between their parents. Seeds and fruits of the three hybrids are intermediate in size and weight between their parents.
Female flowers of C. No. 3 were not produced until the end of August, however, two hybrids, C. No. 1×C. No. 3 and C. No. 3×V. No. 1 produced female flowers normally as early as the beginning of July.
All hybrids showed hybrid vigor and were resistant to Fusarium wilt.

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In order to inquire into the possible role of flavine and pteridine in the tumor-formation of Drosophila melanogaster, early third-instar larvae of wild, v, tu, and v tu flies have been investigated with the following results: 1) Iso-xanthopterine and flavine, probably flavine-adenine-di-nucleotide, were extracted from the materials and identified electrophoretically, paper-chromatographically and fluoro-spectropho-tometrically. 2) Iso-xanthopterine and flavine were quantatively measured with the Beckman-spectrophotometer with the use of extracts from the paper-chromatograms of larvae which were cultured in synthetic media different in quantity of riboflavine and xanthopterine.
Melanotic tumor-incidence and viability of flies cultured in the media with different amounts of riboflavine and xanthopterine were also investigated.
Based on the results of the above experiments, the suggestion may be possible that flavine is intimately related to the tumorformation itself in competition with isoxanthopterine.
A scheme was presented to illustrated melanization, tryptophane metabolic pathway, and metal, flavine and iso-xanthopterine metabolisms in relation to the formation of the melanotic tumor in Drosophila.

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T. Timopheevi (AAGG) と Ae. squarrosa 同質四倍体 (DDDD) との交雑を行なって6個体の F₁ (AGDD) を得た。この F₁ の中5個体は 2n=28で両親の配偶子染色体数の和に等しいが, 残る1個体は2n=29で1本だけ多い (AGDD+1)。
2n=28の F₁ の染色体対合は70.3%で PMC で6～7, 29.7%で8～10の二価染色体がかぞえられた。同時に4.1%の PMC で 0～2_III と0.2%で 0～1_IV の多価染色体もみられた。1細胞あたりの平均対合は 0.0016_IV+0.0428_III+7.2476_II+13.37_I である (第1, 2表)。
この F₁ のゲノム構成により最高対合の 10_II のうち 7_II は 4x-Ae. squarrosa の同親対合 (D-D) であることは明らかであるから, のこる 3_II は T. Timopheevi の同親対合 (A-G) でなければならない。対合型の頻度から D-D 対合を除いて AG ゲノム間の対合量を計算すれば5個体平均4.71%で (第2表), これはすてに報ぜられた Emmer コムギの AB ゲノム間のそれ(木原1936, 近藤•釜野井1955～'58) に比べていくらか高い (第3表)。
多価染色体について三価は D-D の対合に A または G の1～2染色体が, 四価は D-D にそれと部分相同な A と G の染色体が対合して形成されたと思われる。
2n=29 F₁ の結果は第4表に示された。染色体対合の状態から, 1個余計な染色体は D ゲノムに属すると思われ, 4x-Ae. squarrosa に生じた DD+1 配偶子に T. Timopheevi の AG 配偶子が結合した結果てあろう。この個体の AG ゲノム間の対合は2n=28の F₁ と大差はない。
この実験を行なうにあたり多大な便宜を与えられ, 終始指導くださった中島吾一教授にあつく御礼申し上げる。

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MTK-肉腫 II の累代移植中に, 従来から存在している大形の V 型染色体2個を有する種族細胞に代って, 2個の V 型染色体に加えて submedian centromere の大形の染色体1個をもつ新しい種族細胞が比較的高率に観察された。この新しい種族細胞と従来から存在する 2V 型の種族細胞の行動を主に累代移植において観察した。また, それら2種の種族細胞の核型を比較することによって, 新しい種族細胞が従来から存在する 2V 型の細胞のもつ最大形の T染色体の pericentric inversion などによって由来したのてはないかと推論した。
646移植世代の調査においては以前から存在していた 2V 型の種族細胞は発見されなくなり, 完全に新しい型の種族細胞がそれにおき代った。この型の種族細胞は single cell clone として保存された。

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