NOTES ON BRANCH IOBDELLA. 1 05 



seem to indicate that this mass was a very much enlarged cell. 

 One animal showed a few small ova in the edge of this mass ad- 

 jacent to the ovary but in all other animals there was a clearly 

 defined outline between the ova and this mass, which indicated 

 unmistakably that the ova cells were in the ovary. This nutritive 

 mass shows two clearly defined regions, a dorsal and ventral. The 

 dorsal portion contains many small round bodies very uniform in 

 size in a protoplasmic matrix. These bodies take a basic stain 

 while Bordeaux red colors the matrix ; the ventral region does not 

 contain these bodies, nor is it composed of granular protoplasm but 

 yet it takes a basic stain. Its appearance in the fixed state suggests 

 that it exists as fluid in the living animal. When the egg of the 

 hydroid Clava is stained as above and viewed with the oil immer- 

 sion lens, the conditions are so nearly identical that unless one knew 

 in advance I very much doubt his ability to distinguish the two 

 as belonging to different species. It is interesting to find this 

 similarity in two such widely separated animals and it also helps 

 to interpret the conditions in Branchiobdella instability. These 

 bodies are interpreted as nutritive by Hargitt, 1 probably of a proteid 

 nature. In Branchiobdella, I am inclined to believe that this nutri- 

 tive mass is discharged into the cocoon where it nourishes the 

 growing worms. 



Voigt finds the beginning of what he designates a degenera- 

 tion process. This process consists in the deposition of fat- 

 bodies in certain ova but no such large size is reported nor is the 

 change limited to one cell. Of course one can not be sure that 

 but one cell has taken part in the formation of this large nutri- 

 tive cell for the process may involve the growth of one cell at 

 the expense of many others as is so often the case in the growth 

 of eggs. But that this change is a fat-forming process is much 

 to be doubted as no fat reactions were obtained. It is probably 

 rather a normal growth process, the nutrition being stored in 

 this special cell rather than in the cytoplasm of each egg. 



What has already been said for the appearance of the ovary 

 and manner of division may be repeated for the cells in the tes- 

 tes. In size, shape, reaction to stain, and appearance, they are 



1 Hargitt, C. W., "The Organization and Early Development of the Egg of Clava 

 leptostyla," in press, Kn>L. BULL. 



