MORPHOLOGY OF CYPRINODONT FISHES. 



IT 



than in N'eostethus, and the anal fin is much longer, having 

 26 to 28 rays. Correlated with this is the shorter abdominal 

 region, the smaller number of prjecaudal vertebrae (11 or 12), and 

 the larger number of caudal vertebrae (26 or 27) {of. PI. I. A). 

 The visceral anatomy is as in N'eostethus. 



6. Structure of Mais Phallostethus dunckeri. 



In addition to the diffei'ences from N'eostethus described above 

 for t[ie female, the male Phallostethus has many distinctive 

 features. 



a. ExTERN-Aii Characters. 



Total length 25 mm. The priapium (text-iig. 13) is much 

 more prominent than in Neostethus ; the grooves between it and 



Text- figure 1.3. 



Phallostethus dunckeri, J . Head and priapiura from the proctal and 



aproctal sides (X 10). 



tx., toxactinium; ct., ctenactinium; jjy., pulvinulus; a., anus; u., opening of 



ureter ; v.d., terminal coil of vas deferens. 



the body of the fish are not glandular and are of equal size ; they 

 increase in depth posteriorly and meet behind the priapium to 

 Proc. Zool. See— 1916, No. II. 2 



