A MODIFICATION OF THE URODELE TESTIS. 



149 



is Fig. 8), around which are lobules, radially arranged as in 

 the testis proper, but of much smaller size. These small lobules 

 contain, at their apices, primary spermatogonia of the usual type. 

 The peripheral portions of the lobules are filled with cells of 

 variou- type-: a few secondary spermatogonia, an occasional 

 growing or dividing spermatocyte, or small group of spermatids. 

 and degenerating germ cells or cell debris amonu -mattered 

 Srrtoli . dl- ^s. 8 and 9). The lobules of the te-ti- proper 



bd 



ps sc 



(^ ;^/* 



V ^ . > *z^ 



l'i.. 'i I ' l<il)iilcs of tlic caudal appendage of /' n Rlutinosus in late 



June, r.iiin-r.t hit -ila sketch to show contents of lobule in xn-.itrr .1. tail. L.c.d., 



;ii(lin;il n.lli-rtiiiK duct; b.d.. branch of longitudiiuil duct K-aditiK tn li.lmli-; 



prini.u\ spermatogonium of lobule apex; s.c., S it^li <rll (t'ulliclc cell); p., 



piviinriit ' i-llf MI tunic and septa; m.. mesothelial covering <>l t. -t is; s., <pt-nnatocyte 



rmatogonium; i.e., interstitial crll -hrath anpiiinl lotiuk-; d., 



degenerating n-!U i d.-hris from same. 



contain, at the -ame time of the year, traii-tWinm.; spi-nnatids, 

 dividing -pcnnatoc\ tes, growing spermaioryu>. and spermato- 

 ^oni.i. in the cando-cephalic succession cliarai'ti-ri-tic of thi> and 

 otlu-r I'rodele-. In accordance with the usual |i.-iero-aiHerior 

 development of the u;erm cells in these species (spermatogenetic 



