166 SUB-CLASS GANOIDEI. 



irregular network. No trace of the oviducts has been observed 

 in the male. 



In Amia* there is a testicular network, and the posterior part of 

 the kidney is provided with nephrostomes. In the female the oviduct 

 opens into the body cavity. 



In Polypterus the oviduct is short and opens anteriorly into 

 the body cavity, and posteriorly into the kidney duct just before 

 its union with its fellow. In the male the kidney duct dilates 

 behind and joins its fellow to form a considerable sinus which 

 receives the testis duct of each side and opens to the exterior 

 behind the anus. The testis is an elongated body almost as long 

 as the kidney, to the ventral side of which it is attached. Two 

 parts may be distinguished in it — an anterior dilated portion 

 which forms spermatozoa and is the functional testis, and a 

 posterior streak-like portion — the testis-ridge — in which the 



tig 



Fig. 93 — Diagram of the urinogonital organs of an adult female of Lepidosteus (from Balfour 

 and Parker), od Risht oviduct ; the od which is placed on the upper side of the fisuie 

 points a little to the right of the opening of the oviduct into the dilated lower end of the 

 kidney duct ; ov ovary ; bl urogenital sinus ; tuj urogenital aperture ; sg kidney duct ; 

 the reference line goes a little too far in the figure ; k kidney, ly lymphatic organ. The 

 organs of the right side only are shown. 



testicular tubules are few in number and do not form sperma- 

 tozoa. The testicular tubules, both of testis and testis-ridge, 

 open by numerous short ducts into the testis duct which is a 

 longitudinal canal extending the whole length of the organ close 

 to the ureter. In Polypterus then the testis tubules do not 

 communicate with the kidney tubules, but there is a special testis 

 duct which opens behind into the kidney duct at the point at 

 which the oviduct opens in the female. No trace of oviducts has 

 been seen in the male and there are no nephrostomes in the adult. 



In the Sturgeon there is a testicular network in the male, as was first 

 sho^vn by Rathke, and there are short miillerian ducts in both sexes open- 

 ing widely into the body cavity and behind into the kidney duct. In 

 the female the miillerian duct is of course the oviduct. Open miillerian 

 ducts have been seen in both sexes of Scaphirhynchus and Polyodon, but 

 a testicular network has not yet been seen in those genera. 



* Jungersen, Zool. Anzeiger, 23, 1900, p. 328. 



