300 



PROCEEDINGS OF THE ACADEMY OF 



[April, 



togonia, either singly or in groups, but not yet surrounded by a mem- 

 brane. No early larval material was obtained, so the origin of the- 

 spermatogonia, whether from a "Verson cell," a metamorphosed sper- 

 matogonium, or arising around a supporting follicle cell, cannot be 

 discussed. The primordial germ cells divide and redivide until a certain 

 number of daughter cells is formed, usually from sixteen to twenty- 

 four. These are then grouped into cysts surrounded by connective 

 tissue and containing cells in about the same stage of development. 

 Between this region of the spermatogonia and the spermatocyte of the 

 growth period are found all stages of synizesis and synapsis. 



Throughout the testes, but especially where spermatogonia are 

 changing into spermatocytes, whole cysts of degenerating cells are 

 found; in these the chromatin is gathered into one large or several 

 small, compact, deeply staining granules, while the cytoplasm is gran- 

 ular and stringy. In Auerbach's and other differential stains these 

 granules stain like active chromatin, showing that a chemical change is 

 taking place in them. Though these degenerating cysts are far more 

 common in this region than elsewhere, yet they are found throughout 

 the testes, especially where spermatids are forming. Paulmier (1899) 

 figured and described just such degenerating cells for Anasa tristis; 

 though here they are found only after the spermatogonic and before 

 the spermatocytic stages: their appearance in this region of special 

 growth caused Paulmier to interpret them as "food cells." Munson 

 (1906) suggests that a cause for disintegration may be found in the 

 failure of the chromatin to secrete karyolymph. Dederer's (1907) 



