SOUTH AMERICAN NEMATOGNATIII. 29 



tinned to the dorsal; fontanel extending to base of occipital 

 process. Orbit without a free margin. Dorsal and pecto- 

 ral without spines; ventrais under anterior half of dorsal; 

 anal long. Allied to Heptapterus. 



Acentronichthys leptos. 



Type, No. 7532; oue specimea, .105 m. Sao Matbeos, Hartt & Cope- 

 land. 



Extremely elongate, depth of caudal peduncle little less 

 than the greatest depth. 



Eye minute, one orbital diameter nearer to tip of snout 

 than to end of opercle. Maxillary barbels reaching beyond 

 middle of pectoral. Adipose fin long and low, its origin in 

 advance of the anal, confluent luith the caudal Jin. Caudal 

 with numerous accessory rays. Ventrais inserted below 

 the Jirst dorsal ray. Brownish, with traces of a dai^k lateral 

 band ; a dark bar extending forward from eye; two dark 

 lines on base of caudal and parallel with its root. 



Head Ih', depth 10; D. 7; A. 19. 



XV. b. Nemuroglanis gen. nov. 



Type, Nemuroglanis lanceolaius sp. nov. 



This genus belongs to the Pimelodinte with teeth on the 

 Yomer; its relationships are not well made out. 



Caudal long lanceolate; adipose fin long and low, joined 

 to the caudal. No evident occipital process. No bucklers 

 in front of the dorsal which is placed over the ventrais. 

 Vomer with teeth. 



Nemuroglanis lanceolatus. 



Type, No. 8169; one specimen, .035 m. Jutahy, Thayer Expedition. 



Elongate slender, tail compressed, head and body de- 

 pressed. 



Eye 2 -2 1 in snout which is equal to the interorbital, and 

 2J in the head. 



Maxillary barbels reaching beyond origin of the dorsal. 



