)33 



v.ef.col'- 



v.ef.ts 



The term "epididymis" is a very unsatisfactory one and should 

 no longer be used, as it is necessary to distinguish clearly between 

 the coiled anterior end of the spermiduct (== vas deferens, Wolffian 

 duct, mesonephric duct) and the so-called sexual portion (anterior 

 portion or "cranial zone") of the mesonephros of Plagiostomes. 



Two portions of the mesonephros can be plainly distinguished, 

 the function of the anterior of which ("Leydig's gland") is apparently 

 to secrete the substance 

 by which the sperms are 

 bound together in the 

 spermiduct to form „sper- 

 matophores". The greater 

 part of this portion con- 

 sists of small glandular 

 tubules , without Mal- 

 pighian bodies; but in 

 addition to these, larger 



segmentally arranged 

 tubules are present; — 

 these open into the sper- 

 miduct (Figs. 2 and 3). 

 The posterior portion 

 ("caudal zone") serves as 

 the functional kidney: it 

 possesses numerous Mal- 

 pighian bodies and is 

 provided with special 

 ureters. The whole of 

 the mesonephros is seg- 

 mented. 



The bean-shaped testis 

 is suspended by a mes- 

 orchium in which blood- 

 vessels and the fine 

 efl'erent ducts run. The 

 peritoneum is folded on 

 the dorsal surface of the 

 testis between a pyrami- 

 dal area in the centre of 

 this region and its inner border, and a space is thus enclosed between 

 testis and peritoneum. The ventral surface of the fresh testis presents 

 two well-marked regions, — a green medullary, and a white cortical 



Fig. 1. Right testis with anterior end of meso- 

 nephros and spermiduct. Ventral aspect (X !)• <^, 

 b, c Regions through which sections are drawn in 

 Figs. 2 — 4. h.v. blood vessel; m.d. Miillerian duct; 

 ms. mesonephros ("Leydig's gland") ; sp.d. spermi- 

 duct ; ts. testis ; v.ef. efferent ducts of testis ; v.ef.ts. 

 network of effei-ent ducts on testis; v.ef. col. longitu- 

 dinal collector of efferent ducts; v.ef. col' region at 

 which the collector becomes continuous with the spermi- 

 duct; vs. seminal vesicle. 



