238 SIDNEY I. KORNHAUSER 



Many testes show a central core of heterogeneous material 

 made up of degenerating cysts. This looks much like the stream 

 of food seen passing from the terminal chamber to the growing 

 oocytes of telotrophic insect ovarioles. It is not the purpose 

 of the present paper to describe the details of the spermatogenesis 

 or the cytology of degeneration, although the author hopes to 

 attack these questions at another time. 



The ovaries are composed of very long, and much attenuated 

 tubules, each fastened at its narrow, cephalic end by a terminal 

 filament reaching to the dorsal body wall. The sheath of each 

 ovariole is composed largely of tracheal tubules, .and undergoes 

 rhythmic pulsations. The space between the egg string and this 

 sheath is filled with a coagulable fluid. The cephalic tip of each 

 ovariole, just caudad to the attachment of the terminal filament, 

 is occupied by a Keimpolster; then follow oogonia, showing an 

 occasional mitosis; while a trifle more caudad one may find pairs 

 of oogonia both in the same mitotic phase. About one-tenth of a 

 millimeter from the Keimpolster occur the ultimate oogonial 

 mitoses. Here four cells all in the- same stage of mitosis may be 

 found, and each cell gives rise to an oocyte and a nurse cell which 

 continue in close connection and accompany each other from 

 this time until the end of the growth period. Syndesis occurs 

 immediately after the differential mitosis, the oocyte here out- 

 stripping its sister nurse cell in size. Soon, however, the nurse 

 grows much larger than the oocyte, and, at about six-tenths of 

 a millimeter from the Keimpolster, they orient in single file 

 (oocyte, caudad; nurse cell, cephalad), acquire follicular walls, 

 and proceed in the accumulation of yolk material. The large 

 nurse cell with irregular nucleus is surpassed finally in size by 

 the oocyte, and becomes a small cap on the cephalic end of the 

 ovum. 



5. THE DIPLOID CHROMOSOMES 



A. The female 



Oogonia in their ultimate mitoses show 26 clear, distinct chro- 

 mosomes, well separated from one another. Numerous drawings 

 were made and the number 26 established without doubt. Fig- 



