DEVELOPMENT OF SPERMATOBIUM. 1 7 



sporoblasts with inclosing membrane, the outHne of which 

 is more or less distinct, accordingly as the spheres are 

 packed closer or looser together. 



4. The division of the micronuclei is not effected by 

 the budding process, but by division in equal parts by 

 caryokinesis. 



DIVISION BY CARYOKINESIS. 



After the cytospheres have been attracted into sporo- 

 blasts, each one surrounded by a thin membrane, the 

 micronucleus begins again to divide. But now the 

 division is not effected by budding but by a distinct ca- 

 ryokinesis. Small chromosomes may be seen scattered 

 about at first irregularly; later they congregate at the 

 equator, and finally caryokinesis takes place. I have, 

 however, not been able to observe either asters or centro- 

 somes, the highly refractive cytospheres so far obscuring 

 observation. 



Fig. 12 represents such a sporoblast with a single 

 micronucleus. In Fig. 13 the nucleus has divided into 

 two, which have moved to opposite poles, and these sec- 

 ondary micronuclei have again divided. The two upper 

 ones are yet connected by a caryoplasmic filament. 



DISINTEGRATION OF THE NUCLEOLUS. 



The first indication of a disintegration of the nucleolus 

 is a blurred outline, caused by small irregular drops, 

 staining exactly as the nucleolus, appearing on the outer 

 circular surface of the nucleolus (fig. 8dJ. Smaller, 

 more or less irregular globules are seen in the caryo.plasm 

 near by, and in more advanced specimens nucleolar frag- 

 ments are seen in the various or in some of the cary- 

 oplasmic nodes. Sometimes one of these new nucleoli 

 are larger than others, staining either darker or lighter 

 than the surrounding caryoplasm. Around such caryo- 



2d Ssr., Vol. V. ( 2 ) May 18, 1895. 



