1. Forty-two mutant characters of Drosophila ananassae, which were newly found, following the first eleven mutants, are described, with their origins, characteristics, and linkage data.
2. Of these mutants, thirteen are sex-linked. They are achaete (ac), clumploid (cl), cut³ (ct³), extended-b (ex-b), Golf (Gf), lethal-3 (l-3), lethal-4 (l-4), purplish (ph), scute (sc), scute² (sc²), scute³ (sc³), vesiculated (vs), and yellow (y). Although not separable from the heterozygous flies, the homozygotes of Golf, a dominant character, are viable.
3. Beaded (Bd), broken-b (bn-b), chilblained (ch), contracted (cnt), crippled (cp), Dichaete (D), extended (ex), hooked (hk), missing (ms), missing-b (ms-b), Minute-IIb (M-IIb), Off (Off), Puffed (Pu), roof (rf), and rough (ro) are described as mutants in the second chromosome. Among the dominant genes, Off was known to be viable when homozygous. As to the rough gene, it was peculiar in that the character could be expressed only when accompanied with a Plexate gene.
4. In the third chromosome, there newly appeared nine mutants, such as crooked-b (ck-b), erect (er), Minute-IIIc (M-IIIc), Minute-IIId (M-IIId), rumpled (rm), rippled (rp), pski-III (sk-III), warped (wp), and wavy (wy).
5. Bobbed-IV (bb-IV), which was first described as bobbed, has long been known to be only a mutant found in the fourth chromosome. Three mutant genes are newly added, namely, Minute-IVa (M-IVa), mottled (mo), and Shaven (Sv).
6. A certain power to enhance crossing over, affecting both sexes, seems to be associated with every Minute-IIb, Minute-IIIc, and Minute-IVa, with the result that provided any one of these Minutes are associated, the male crossing over occurs in the natural condition, whereas in the female associated with any one of these Minutes, crossing over is increased.
7. Various kinds of inversion seem to appear quite often in this species. Puffed, perhaps also Dichaete and Beaded, should be accompanied with inversion CIIL, a subterminal inversion having the power to suppress crossing over in the left arm of the second chromosome, while a small inversion may be associated with the X-chromosome of lethal-4 or w f², which, however, has not yet been recognized cytologically, only showing that it may suppress crossing over slightly at the region near w f².

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The chromosomes of Hemigrapsus sanguineus (de HAAN), a species of the shore-crab (Varuninae, Grapsidae), are described in the present paper. The diploid number of chromosomes is 128, as determined in spermatogonia (Figs. 1-3), while the haploid number is 64 as counted in both the primary and secondary spermatocytes (Figs. 4-9, primary spermatocyte; Figs. 16-18, secondary spermatocyte). Sex-chromosomes of X-Y type are found in the primary spermatocyte division (Figs. 10-15). They invariably take the central position of the metaphase plate, and segregate earlier than autosomes. The relative magnitude existing between them seems to be constant, the small one (Y) being approximately one third the size of the large one (X). It was quite difficult, however, to distinguish these two particular chromosomes among the chromosomes of the spermatogonium or of the secondary spermatocyte. In respect to the constitution and behavior of the sex-chromosomes the present species shows a close resemblance to Plagusia dentipes and Eriocheir japonicus, previously recorded by the present author (cf. NIIYAMA 1937), in parallel to their taxonomical relationships.

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This investigation has been attempted to obtain some knowledge of the inheritance of root color in the radish. Five color types are treated in this paper, i.e. white, red, purple, yellow and black. These results may be summarized as follows:
1. In the cross between red and white, and the reciprocal, the F₁ is purple, and the F₂ consists of 9 purple: 3 red: 4 white (Table 2). Consequently two factors are assumed; (1) R, a factor for production of red pigment, and (2) B, a factor which produces no color alone, but acts in conjunction with R factor to produce purple pigment.
It seems that the genotype of red may be represented by RRbb and that of white by rrBB.
2. When purple is crossed with white, the F₁ is purple, and the F₂ is in the ratio 3 purple to I white. The reciprocal also supports the single factor concept (Table 3). These facts suggest that the genotype of purple may be designated by RRBB.
3. In the combination between yellow and white, yellow is dominant over white in the F₁, and a 3:1 ratio of yellow to white appears in the F₂ (Table 4).
4. The F₁ of the cross between white and black is black, and the F₂ consists of 3 black: 1 white (Table 5). A close 1:1 ratio of black to white is obtained in the back cross generation of the F₁×white (Table 6). It is evident that black is a simple dominant to white.
5. In the cross between red and yellow the F₁ is purple, and the F₂ conforms to the ratio 9 purple: 3 red: 3 yellow: 1 white (Table 8).
6. Upon selfing variety Cincinnati Market gives a few yellow seedlings which soon fail to develop. The F₁ of the cross between Cincinnati Market and Golden Ball is normal green, and the F₂ consists of two distinctly different families, one of which gives an approximate 3:1 ratio of green to yellow, and the other breeds true for normal green (Table 9). X_a, a factor for normal green and x_a, a factor for yellow are assumed. Thus the genotype of Cincinnati Market may be represented by X_ax_a.
7. The F₁ of the cross between yellow and purple is purple, and the F₂ is in the ratio 12 purple: 3 yellow: 1 white (Table 10).
8. Purple is dominant over red in a monohybrid relation (Table 11).
9. The F₁ of the cross between red and black is blackish purple, and the F₂ ratio is 27 blackish purple; 9 purple: 9 blackish red: 3 red: 12 black: 4 white (Table 12).
10. In the cross between purple and black the F₁ is blackish purple, and the F₂ is in the typical dihybrid ratio 9 blackish purple: 3 purple: 3 black: 1 white.
11. Black is dominant over yellow in the F₁, and a close 3 black to I yellow ratio is obtained in the F₂ (Table 15). Black, yellow and white are so related genetically that any two of them taken together give results conforming to a unifactorial scheme. Consequently it seems probable that the factor for black constitutes a set of multiple allelomorphs with two factors for yellow and white.
12. The probable genotypes of root colors in the radish are assumed as follows:
rrBByy white
RRbbyy red
RRBByy purple
rrBBYY or rrBbYY yellow
rrBBY^bY^b black
In addition to these formulae, C factor for chromogenic substance may be assumed respectively (Table 16).

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Das heterozygotische Männchen von zwei rezessiven geschlechtsgebundenen Faktoren, os{ölig-durchsichtbare Haut(Abb. 4.)} und e(lange Abdominalsegmente), wurde mit Röntgenstrahlen bestrahlt und demnach mit dem Weibchen, das zwei dominante Faktoren Os (Abb. 1.) und E trägt, gekreuzt. In den F₁-Individuen traten ausnahmsweise drei os-scheckige Raupen ausser den erwarteten auf. Nach genetischen und zytologischen Analysen wurde es klar gemacht, dass jedes dieser os-scheckigen Raupen (Mos) ein oder zwei Os-tragende Z-Chromosomfragmenten ausser den normalen Chromosompaaren besizt, d.h., eine Fragmentation zwischen Os und E von Z-Chromosom des Vaters aufgetreten hat. Dieses kleine Chromosomfragment verhält sich gewöhnlich wie ein vollständiges Chromosom, abgesehen von den Fällen, wo ihre Elimination (Abb. 7, 12, 13.) öfters nicht nur in der Somatogenese sondern auch in der Gametogenese vorkommt. Die Häufigkeit der Elimination ist grösser in der Spermato-genese als in der Ovogenese. Der Hautteil, bei welchem die Elimination stattfand, wird ölig-durchsichtbar (os) im Gegensatz zu anderen normalen, welcher das Os Gen vom Fragmentchromosom hat, und daher wird eine Mosaikhaut gebildet.
Die heterozygotischen Mos Individuen (Abb. 3.), die von der Haut mit vielen ölig-durchsichtbaren Flecken bekleidet werden, haben ausser n=28 Chromosomen ein überzähliges Chromosomfragment (Abb. 5.), das in der Metaphase der ersten Reifungsteilung meistens ein besonderes Verhältnis stattfindet und als ein Univalent gefunden wird. In der zweiten Reifungsteilung liegt dieses Fragment auch ausser anderen Chromosomen und nimmt gewöhnlich die Aequationsteilung (Abb. 8.), aber das Nichttrennen kommt selten vor. Das Grössenverhältnis vom Fragmentchromosom gegen normales ist etwa von 1/4:1 bis zu 1/7:1. Alle heterozygotische Individuen mit einem Fragment beweisen dieselbe Lebensfähigkeit wie die normalen Raupen.
Die homozygotischen Mos Individuen (Abb, 2.) haben scheckige Haut mit wenigen und sehr kleinen, zerstreuten öligen Teilen oder vollkommene normale undurchsichtbare Haut. In der Metaphase der ersten Reifungsteilung haben diese Individuen immer zwei Fragmentchromosomen als Univalenten (Abb. 10.), welche nach einem Pol gehen, d. h., das Nichttrennen auftritt (Abb. 11.). Auch werden aber solche Fälle beobachten, in denen jede Zellen je ein Fragment erhalten (Abb. 9.). Die Fragmenten werden oft in diesem Fall eliminiert (Abb. 12.). In dem Weibchen von einem Stamm wird nur das Nichttrennen und keine Elimination erkannt. In der zweiten Reifungsteilung auch verhalten sich diese zwei Fragmenten besonderes Verhältnis, und nehmen hauptsächlich Aequationsteilung, abgesehen den selten Fällen, in denen das Nichttrennen gefunden wird. Die homozygotischen Individuen sind schwächer als die normalen, und das Weibchen schwächer als das Männchen. Die Individuen, die drei Fragmenten besitzen, mögen vielleicht keine Lebensfähigkeit haben. In den Individuen mit ein oder zwei Fragmenten laufen die Fragmente nach einem Pol oder beiden Polen eher als anderen Chromosomen in den beiden Reifungsteilungen (Abb. 6, 9.).

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