MORPHOLOGY OF CYPRINODONT FISHES. 



15 



•development and are cartilaginous and enclosed in skin ; their 

 final shape is uncertain ; the testis (t.) is fairly large. 



A male of 21 mm. (text-fig. 11, A) has the priapium but little 

 developed and without trace of ctenactinia, but showing a difi'er- 

 ■entiation into an anterior muscidar and a posterior visceral 

 portion ; in this fish the testis is quite small. 



Text-ficjure 11. 



Neostetlms hicornis : immature males ; head and priapium from aproctal side (XlO). 

 Total length of fish : A, 21 mm. ; B, 25 mm. The testis (t.) is shown separatelj'. 



pv., pulvinulus; pva., pulvinular appendage ; ct., ctenactinia; p., seminal papilla; 

 ef., efferent groove. 



A female of 24 mm. is very similar to the female iY. lankesteri, 

 except for the more slender form ; the postanal depression is less 

 developed than in iY. lankesteri, probably because the specimen is 

 not fully adult. 



The male examples are of interest as indicating that the pri- 

 apium develops only as maturity approaches ; presumably males, 

 only a little smaller than the smaller one, would be almost indis- 

 tinguishable from immature females. 



