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R. R. HUMPHREY 



spermatogonia, and remaining enclosed in its original follicle 

 whose cells have divided to keep pace with the increasing number 

 of germ cells. The lobule is in addition invested by its sheath 

 or membrane of connective tissue. By the growth and mat- 

 uration divisions of these cysts of 'secondary' spermatogonia 

 the lobule, now much distended, becomes made up of masses of 

 spermatids, which no longer enclosed in the follicle cells though 



1 



Fig. 1 Longitudinal section of the extreme anterior end of a Desmognathus 

 testis. The central collecting duct is shown, bordered by primary spermato- 

 gonia with their surrounding follicle cells. 



Fig. 2 Longitudinal section of a Desmognathus testis, showing a region 

 somewhat posterior to that pictured in figure 1. The developing lobules are 

 here well defined, although containing as yet only primary spermatogonia. Their 

 connection with the central collecting duct is now evident. Only flattened stro- 

 mal cells appear between the lobules. 



in close relationship thereto, undergo the well-known trans- 

 formation changes, and eventually pass out of the lobule as the 

 spermatozoa. 



The development of the lobule needs for the present no more 

 detailed consideration than that given above; for greater detail 

 the various papers on the spermatogenesis of urodeles may be con- 

 sulted. It should be emphasized, however, that all the cells of 

 the lobule undergo the various developmental changes synchro- 

 nously, or approximately so; hence the lobule, in successive periods. 



