A MODIFICATION OF THE URODELE TESTI-. l6l 



cells. Hence an appendage of excessive length would tend to 

 disappear in the course of phylogeny, the strains surviving being 

 those in which only a more limited degeneration occurs. 



In one male however, an unusual type of appendage, fully half 

 the length of the testis has been noted. This male, a Gyrhiopiiilns 

 freshly raptured on August 15, is of large size, and is po--ibly a 

 senile individual or one unfavorably affected by di-ease or other 

 factors. At any rate, the spermatids in the entire caudal half of 

 the te-ti- ha\e failed to trail-form, degenerating as they de- 

 \eloped. Thi- degeneration, it may be noted, is of evil- nion- 

 advanced in development than those who-r de^em-ration in 

 \\inter ordinarily gives rise to the appendage in thi- 

 '1 In- grouing -permatocytes, though unable to Mir\i\v \\inter 

 COnditions, actually complete their growth period and maturation 

 divi-ions in ihis specimen, only to have the re-Milting -permatids 

 de-tro\rd by -ii bsequcn t degeneration. 



\nother umiMial type of appendage was found in a /'.;!) \ 



male captured in early July and kept in the- laboratory fi.r a 

 period of about ten days. The oldest spermatids in tin- male 

 \\ere probabK beginning their transformation at tin- time of it> 

 capture, ^ince, ten days later, developing -pcrmato/o.i \\-n- 



cut in a fe\\ of the most caudal lobules of the te-ti-. A|- 

 pareniK only those spermatids having reache-< I a lertain >tai;e of 

 nan-formation before the period of captivit>' be^an \\ere able in 

 tontimie- their normal differentiation, since in lobule- more 

 anterior in position, in \\hidi the spermatids \\ould have been 



ad\ anced. t heir continued development had become abnormal 

 in character. In these lobules, as a result, variou- bi/anv t\|>-s 

 ot -|>ei niato/oa were present, including evil- similar in form to 

 the mammalian spermatozoon. In still more anterior lobule- 

 the young* rmatids had disappeareel completely, probably 



\\ithoui evei beginning transformation; cephalad of this region 

 \\ere lobule- iii which the spermatid degeneration \va- >till going 

 on. Voungei -ta.nes (spermatogonia, gmuin^ and di\-iding 

 spermatocytes) show no unusual features. AjiparentK those 

 germ cell- mo-i -usevptible to environmental e-fk-ct are tho-e 

 most ad\ anced in development at least u\> to a certain sta^e in 

 -permalid transformation. After this stage the cell- are more 



resistant, as e\ idem ed by the normal -pcrmato/oa in the most 

 11 



