MORPHOLOGY OF CYPRINODONT FJSUES, 



19 



proximal part of the first rib of the proctal side instead of to 

 the transverse process of the third vertebra : and (2) there is a 

 toxactinial muscle (text-fig. 15, txm.), that lies outside the longi- 

 tudinal muscle of the proctal side, ends posteriorly between the 

 coils of the vas deferens, and anteriorly is inserted on the base of 

 the toxactinium. 



d. YiscERA (text-fig. 14). 



A dijQference from Neostethus is that the ureter {u.) accompanies 

 the intestine (i.) and opens behind the anus ; of more importance 

 are differences in the testis and vas deferens (vd.). The testis 

 (PI. lY. A) has no tubules lined with a distinct epithelium, even 

 near the origin of the vas deferens, which leaves the testis {t.) 

 anteriorly and at once becomes coiled up into a mass that lies in 

 front of and to the right side of the testis ; this " epididymis " is 

 ^simi]ar to the testis in form and is not much less than it in size 



Text-fiofure 14. 



Visceral anatomy of PhaUostetuus dunckeri, S ; the livev, etc., removed (X 10). 



ce., oesophagus ; s., stomach ; ?'., intestine ; A;., kidney; m., ureter ; #., testis; 

 v.d., vas deferens; a., air-bladder. 



(text-fig. 15, B); the vas deferens emerges from its narrowed 

 •anterior end, enters the priapium, and runs backwards on the 

 aproctal side to above the base of the ctenactinium, then across 

 to the proctal side before coiling round in a complete circle and 

 opening ventrally to the exteiior in a short seminal papilla behind 

 the base of the ctenactinium. 



The vas deferens is lined with a glandular epithelium ; in the 

 " epididymis " this is formed of long columnar cells with basal 

 nuclei (PI. TV. B). The outer fibrous layer is quite thin, except 

 in the terminal coil, where it is thick. The lumen contains 

 spermatozoa, which seem to adhere together, their heads forming 

 more or less convex plates, whilst their tails are dependent from 

 the concave surfaces. However, this structure cannot be very 

 definitely made out from the sections, but it seems clear that 

 there are no spermatophores of the type described in Neostethus. 



2* 



