dec. i9io.] KUWADA.-A CYTOLOG. STUD. OF ORYZA SATIVA. 273 



from individuals with the dark violet stimga or with the colour- 

 ed glumes or leaves. The investigations of such materials have 

 shown, however, that in all these cases the plants are provided 

 with 12 gemini which are as large as those of ' Shinriki.' This 

 abnormal case is certainly of an interest, but the impossibility 

 of the identification of the plant itself makes it difficult to carry 

 further investigations on this point for the present. 



II. Behavior of Chromosomes in the Somatic Cell. 



Here a brief account of the diploid chromosomes may be 

 given. The number of chromosomes in the nucellar tissue is 24 

 (Text-fig. A. c). The paired arrangement of chromosomes 

 which was noted at first by Strasburger (12, P. 19) and after- 

 wards by several authors is clearly seen. They are sometimes 

 closely attached end to end, and present an appearance of a 

 single bent chromosome, and the differences of their size and shape 

 are well shown. Some of the paired chromosomes are smaller 

 than others as found in the abnormal case of the heterotype 

 division above stated. Very often, however, I have met with cases 

 where there w r ere a greater number of paired chromosomes ; 

 in one case even more than 16 pairs were observed, some of 

 them being smaller than the others (Text-fig. A. d)., 



III. Embryosac and the Endosperm-Formation. 



The embryosac-mother-cell is formed subepidermally (Text- 

 fig. B. a). The maiosis takes place in the same way as in the 

 pollen-mother-cells. The chromatin-masses in paired arrange- 

 ment are also here observed in the pre-synaptic stage (Fig. 18), 

 and the actual union of the spirem-threads takes place in the 

 same stage as in the case of pollen-mother-cells (Fig. 19). The 

 four macrospores are formed in a vertical row, and as usual 

 only the lowest one develops to be the embryosac. The upper 

 sister-cells are gradually disorganized and remain for a time as 

 deeply staining masses which finally disappear altogether. The 

 embryosac contains at first as usual an egg-cell, two synergidas, 



