SOUTH AMERICAN NEMATOGNATHI. 201 



Eye large, 5 in head, 2^ in snout, 1J in interorbital, 

 1J diameters behind the rictus. 



Gill - membranes separate almost to angle of mouth ; 

 gill-rakers overlapping, 4 + 11. 



Dorsal spine slender, weak recurved teeth behind; 

 equidistant from snout and middle of adipose dorsal and 

 from bases of pectoral and ventral; If in head. 



Base of adipose about twice length of anal. 



Caudal deeply forked, the outer lobes long and pointed, 

 the rays simple or only twice branched. 



Ventrals extending one-half their length beyond vent ; 

 distance from vent to anal 4 diameters of eye. 



Pectoral spine long and slender, roughened anteriorly, 

 with strong teeth posteriorly; 1J in head, scarcely shorter 

 than the rays. 



Head 3f ; depth 6; Br. 11?; D. I, 6; A. 12. 



XXXII. ? 

 147. ? lutkeni. 



Platystoma lutkeni Steindachner, SB. Ak. Wien, Ixxiv, 1876, Ich- 



thyol. Beitr. iv, 59, plate 13 (Amazon). 

 Habitat: Amazon. 



This species is known only from the types. Its den- 

 tition would prove it distinct from any of the genera 

 enumerated, but as we have not seen any specimens we 

 can not decide about this point. 



Palatine and vomerine teeth 

 both present and forming a 

 shallow band immediately be- 

 hind the wide intermaxillary 

 band; teeth villiform. Upper 

 jaw little projecting. Maxil- 

 lary barbels to base or tip of ^ 

 ventrals. Adipose fin much longer than the anal. Occip- 

 ital process reaching the very long dorsal plate. Pectoral 

 spine serrate behind, broader than the dorsal spine. 



