42 HARLEY N, GOULD 



ably present. During the passage of sperm into the wall and 

 the shrinkage of the vesicle, the cilia seem to be in part destroyed. 

 New ones probably appear later. 



b. The penis and sperm groove. The loss of the male condition 

 is accompanied by the degeneration of the penis (table 3). The 

 latter process takes place within two or three weeks after the 

 regression of the testis begins, but is not uniform enough in its 

 occurrence to be used as an exact indication of the state of the 

 gonad and vesicle. While degenerating the end of the penis 

 becomes brown, and cells are evidently being sloughed off at 

 this point, for the whole organ becomes shorter and shorter 

 until only a brown stump is left; and this too finally disappears 

 leaving no trace whatever. The sperm groove also becomes 

 flattened out and loses its cilia. 



Development of the accessory feinale organs, a. The oviduct. 

 The further history of the efferent duct depends on the behavior 

 of the gonad, as is the case at an earlier period of hfe. As has 

 been made certain, the goniduct of a small male whose testis 

 has degenerated may return to the rudimentary condition seen 

 in the neuter animals, so that no evidence remains of the former 

 male state unless the specimen has been marked and observed 

 from the time when it bore the external genitalia of the male. 

 In the following section we will consider the changes in the 

 goniduct of a large degenerate male, in whose gonad young 

 oocytes begin to appear. 



The distal part of the goniduct (vas deferens in the male 

 phase) does not change much during the degeneration of the 

 testis, but remains a small cihated tube. The wall thickens a 

 little and lightly staining granules appear in the cytoplasm (figs. 

 73, 74). The proximal part, i.e., what was the seminal vesicle, is 

 now an extremely thick-walled structure (figs. 75, 76), still re- 

 taining some of the twists and turns which it formerly had, 

 though they are far less numerous than before. Where the 

 growth of the body is rapid during this period (as shown by the 

 nature of the shell) it is difficult to know how much the seminal 

 vesicle has shrunken, for the loss of the convolutions might be 

 attributed to the elongation of the visceral sac. 



