105 



by ail effeieiit duct. In fi^-. 5 this is tigiired. Only these caudal vasa 



effereiitia are projected on tlie mid-sagittal plane of the testis. Moreover, 



two-single testis tubules, directly 



passing over into the rete testis, 



are sketched; the vas efferens, 



previous to the last, gives off a 



side branch to the last efferent 



duct, but a connection is not 



established, however. 



Two frontal sections of the left 

 testis (long 6, broad 3,5 ni.m.) of 

 a frog in the beginning of the third 

 year (4,75 cm. in length) are 

 reproduced. Fig. 6 shows a section, 

 close to the rete testis, of which 

 different parts are visible. The 

 tubules A, B, 6' and Z) are sepa- 

 rately connected with the lete; 

 tubule B just ends in the rete in 

 the section reproduced; in a neigh- 

 bouring section tubule C is con- 

 nected with this same rete canal. 

 In this figure arrows indicate with 

 which part of the rete a few of testis-plane. Frog from the beginning 

 the testis tubules are connected, of the second year (X 100). 

 When we ti-ace the course of the testis tubules, indicated A, B, C 

 and I) towards the periphery, we see that here also these tubules 

 divide into many others; e.g. tubule A splits up into seven, B into 

 five, C into four and I) into six others. Fig. 7 shows a section of 

 the same testis about halfwa} the periphery. At this level tubule^ 

 has divided into 3 branches (A I— II, AIll—V, A FJ—VJJ), B 

 into three {B V , branched off nearer to the rete is very short), D 

 into four, while tubule C has not divided as yet; this will take 

 place closer to the periphery. The space between the tnbules, being 

 rather wide near the rete, is very narrow at this level. Most tubules 

 end near the periphery ; anastomoses are never found. 



On comparing the testis of a newly metamorphosed frog (fig. 1) 

 with that of a second or third-year one (tigs. 2 — 7), we find that the 

 testis tubules, which are single originally and terminate in blind ends, 

 divide already in the second year into a number of branches (like 

 the fingers of a hand) and that this subdivision has increased in the 



Fig. 5. 

 Projection of the two posterior vasa 

 efferentia on the sagittal longitudinal 



