104 



Fig. 3. 



terminatiiig in Uliiul ends. Tubule A i-ainities into five tubules [A /, 

 AII...AV), H into two tubules {Jil, Bll), while C i-eniains 



single. Ali-eady in fig. 2 it is visible 

 that the tubules A and li divide 

 into a certain nuniber of branches, 

 for these tubules are designated 

 A I— V and B 1 — // in this figure. 

 On comparing figs. 2 and 3 we see 

 that the space between the tubules, 

 the interstitiuni, is larger near to 

 the rete than towards (he periphery. 

 As has already been mentioned, fig. 3 

 is drawn after a section close to the 

 testis-sui'face, so that not all testis 

 Section as in" fig. 2, but more tubules are cut transversely. Many 

 near the periphery (X 100). tubules, which were not cross-CUt, 



were indistinctly visible and for this reason this part of the section 

 is shaded by oblique lines. 



To elucidate the course of the seminiferous tubules, I have projected 

 the circumferences of the testis tubules A, B and C on a sagittal 

 plane of the testis (this plane is marked by a — . — .— line in 

 fig. 3). This is reproduced in fig. 4, in which the course of these 

 tubules can be seen. Moreover it is visible that the ducts of the 

 rete into which the tubules A, 

 B and C pass over, are directly 

 connected with each other. 



The left testis of the same 

 frog was cut transversely. The 

 testis tubules are built in the 

 same manner as those of the 

 right testis. However, on com- 

 paring the form of the tubules 

 of the cranial and caudal part 

 of the left testis with the form 

 of the tubules of the middle 



AïAïïA\B,P.LA^,3^ d 



t..n. 



Fig. 4. 

 Projection of the tubules (designated 

 part of the right testis, we see in figs. 2 and 3) on a sagittal testis- 

 that in the former the number Pl-^ne (X 150). 



of simple, not branching tubules is much larger than in the latter. 

 A peculiarity of this left testis is that the most caudal vas efferens 

 is not connected with the rete testis. In this testis there is a small 

 caudal part, consisting only of three testis tubules, which do not 

 open into the rete, but are directly connected with the mesonephros 



