1922.] 



S. L. Hop A : Central Asiatic Cobitidae. 



81 



Among the specimens from this locality two forms are repre- 

 sented, one in which the caudal peduncle is very low and the com- 

 mencement of the dorsal fin is situated at an equal distance from 

 the tip of the snout and the base of the caudal fin ; while in the 

 other the caudal peduncle is fairly deep and the origin of the 

 dorsal fin is distinctly nearer to the base of the caudal than to the 

 tip of the snout. Most of the females, which are about 54 mm. 

 in length, are full of eggs. The snout is long and pointed and the 

 eyes are situated in the middle of the head. 



Note on the Secondary Sexual Characters of certain 



Species of Cobitid Fishes from high Altitudes 



in Central Asia. 



In the Indian species of the genus Nemachilus which ex- 

 hibit sexual dimorphism the male is provided with " a slit-like 



TEXT-FIG. 4. — Lateral view of head and upper surface of pectoral fin in 

 a male specimen of Nemachilus tibetanus Regan, showing secondary sexual 

 characters. 



deep groove in front of the eye which bends round a small knob- 

 like rounded flap of skin protruding below the anterior one-third 

 of the orbit, the ridge above the groove appearing slightly swollen 

 and cushion-like." The pectoral fins are also modified where 

 " there is a kind of padding and thickening on the upper surface " 

 and " on the padding, minute hooked denticular outgrowths are 

 noticed." These secondary sexual characters were described by 

 Chaudhuri in Nemachilus mackenziei 1 and N. manipurensis 2 and 



I Chaudhuri, Rec. hid, Mus. V, p. 183. 



1 Chaudhuri, Rec. Ind. Mus, VII, p. 443, pi. xl, figs. 4, 4a, 4/;; pi. xli, figs. 

 I , la, lb. 



