EIGENMANN: the freshwater fishes of BRITISH GUIANA 



127 



process reaching last fourth of the pectoral spine; half of the last dorsal ray adnate; 

 caudal peduncle terete ; everywhere tuberculate, nine conspicuous series of tubercles 

 on the tail. 



Dark chocolate, a light saddle between the dorsal and nuchal crest; back be- 

 hind the dorsal with lighter blotches; dorsal, caudal, and anal fins black, their 

 margins white, first rays of dorsal and anal 

 and outer rays of caudal banded; ventrals 

 mottled, margined with white, darkest just 

 below the light edge; pectorals black, last 

 rays with light mottlings; barbels banded. 



10. 



Bunocephalus chamaizelus sp. nov. 

 (Plate II, fig. 1.) 

 Bunocephalus chamaizelus Eigenmann, Repts. 



Princeton Univ. Exp. Patagonia, III, 



1910, 380 (name only). 



Type, 36 mm. Erukin. (Carnegie Mu- 

 seum Catalog of Fishes No. 1556.) 



Cotypes, five specimens, 24-44 mm. 

 Erukin. (C. M. Cat. No. 1557a and b; I. 

 U. Cat. No. 11974.) 



Cotypes, seven specimens, 34-39 mm. 

 and b; I. U. Cat. No. 11975.) 



Cotypes, six specimens, 30-37 mm. Gluck Island, 

 and b; I. U. Cat. No. 11976.) 



Head to gill-opening 5 in the length; greatest width 3.16; distance of dorsal 

 from snout 2.36 in the length; caudal 4.4-6; D. 5; A. 8 or 9, rarely 7; depth of 

 head about 1.5 in distance of pectoral from tip of snout; length of coracoid process 

 about one-half the distance between its bases; anterior margin of coracoid without 

 an externally visible crest; caudal peduncle terete; everywhere tuberculate, the 

 regular rows of the tail somewhat obscured by the intervening tubercles; tubercles 

 on the head variously developed. 



A faint ridge from eye to occiput; occipital with a slight knob, nuchal plate 

 with two, dorsal plate with one, the four in a straight line. 



Maxillary barbel reaching pectorals; pectorals to ventrals in the smaller speci- 

 mens; humeral process reaching third fifth of pectoral spine. 



Lighter or darker sand-color; a dark streak from pectoral forward to mouth 



Fig. 24. Bunocephalus amaurus Eigen- 

 mn. Type. C. M. Cat. No. 1555. 



Tumatumari. (C. M. Cat. No. 1558a 

 (C. M. Cat. No. 1559a 



