58 B. F. LUTMAN. 



primary and secondary spermagonial cells are sharply distin- 

 guished in their division stages while the development of the 

 cysts with their surrounding epithelial cells is almost diagram- 

 matic in its clearness. 



There seems to be a general agreement in the literature that 

 each of the cysts that lie in the follicles of the testes has its 

 origin from a single germ-cell. This conception seems to have 

 originated in the work of ValletteSt. George (12) on the testes of 

 Rana temporaries. He found that if he teased apart the paren- 

 chyma of the testes, groups of cells, that he called spermatocysts, 

 would drop out. These structures had walls of their own in 

 which were imbedded one or two nuclei. St. George believed 

 that each of these cysts arose from a single cell, one of his "Ur- 

 samenzellen." These would correspond to the last of what is 

 now known as the primary spermagonial cells. By the division 

 of these cells there was produced the spermacysts containing the 

 spermagonia; or as now called, the secondary spermagonia. 



Montgomery (10) describes the cysts in Pentatoma but did not 

 work out their origin. The connective tissue network of the 

 young testes contains, he believes, in each mesh a single sperma- 

 gonium or at least only a few spermagonia. These cells divide 

 and the cells produced by their division are surrounded by a 

 cyst-membrane derived from an extension of the connective tissue 

 investment of the follicle. The germ-cells and the cells of the 

 cyst w r alls have then a different origin. 



Several others, among them Henking, Paulmier and McGregor, 

 are mentioned by Sutton (14) as having noted the arrangement 

 into cysts and the cyst walls but none of them seems to have 

 followed their development. 



Sutton (14) in studying the spermagonial divisions in Brack ys- 

 tola magna also worked out fairly completely the development 

 of the cysts. A cyst membrane with nuclei in it is formed even 

 in the two-celled stage of the secondary spermagonia. The c> sts 

 assume a roughly pyramidal shape, the cells inside it largely 

 dividing tangential!} to the surface of the cyst. All the cells 

 in one cyst seem to divide simultaneously producing by means 

 of about eight divisions, 256 cells. The cysts are not attached 

 to the walls of the follicles. 



