114 Annals of the Carnegie Museum. 



In females the ventrals are normal in shape and barely reach the 

 vent. In males the ventrals, although proportionately of the same 

 size, are slightly more lanceolate and are set more closely to the anal, 

 which they overlap for a third of their length. 



40 

 Fig. 2. Diphyacantha choco'ensis Henn. Distal end of intromittent organ. X — • 



No. 13,620, I. U. M. Rio Calima, Colombia. 



12. Diphyacantha chocoensis Henn. sp.nov. (Plate XIX, figs, i and 2.) 

 13618, I. U. M., Type, male, 31 mm. 13619, I. U. M.; 5825 a-j, 



C. M., Paratypes, twenty-five specimens, four males, twenty-one 

 females, 18-35 mm. Small creek near mouth of Rio Calima, a tribu- 

 tary of the lower San Juan, Choco, Colombia. Henn. 



13620, I. U. M. Two males, four females, 22-37 mrti- Rio Calima, 

 small brushy creek near Boca del Guineo. Henn. 

 Head 3.8-4.2; depth at origin of anal, in females 4-4.2, in males 3.8; 

 depth of caudal peduncle 6.5-7 in length without caudal and about 

 1.3 in head. Eye 2.5 in head; 1.5 in interorbital. Premaxillary 

 very short, mandible longer, forming anterior border of mouth, 

 chin steep and oblique, cleft of mouth almost vertical. Upper profile 

 almost horizontal, lower gently curved. 



D. 7; A. 10 (in 12 specimens); P. 12-13; V. 6; scales 28 in a lateral 

 series, which is underlaid by a black canal; 7 in transverse series, 

 exclusive of median dorsal series; 16-18 scales between the large 

 occipital scale and the origin of the dorsal, predorsal region very 

 broad and flat. 



Origin of dorsal far back in both sexes, twice as distant from the 

 anterior margin of the orbit as from the base of the caudal, or equi- 

 distant from the posterior margin of the orbit and the tip of the caudal. 

 Origin of anal in females equidistant from base of caudal, and upper 

 angle of gill-opening, slightly less in length than the head. In males 



