SOUTH AMERICAN NEMATOGNATHI. 291 



Felichthys nodosna Eigenm. & Eigeum. Proc. Cal. Acad. 2d Ser. i, 



154, 1888 (Para; Bahia). 

 Auchenipterus furcatus Cuv. & Val. 1. c, 211, 1840 (Guiana). 

 Habitat: Bahia; Para; Guiana. 



Miiller&Troschel on examination of Bloch's type iden- 

 tify Ail. fitreatus C. & V. with Silurus nodo.Hus Bloch. 



There is great variation in the length of the spines in 

 this species; in a specimen from Bahia the pectoral 

 spines end in a sharp point, and are very long; in the 

 specimens from Para the spines are short and end ab- 

 ruptly, but are prolonged in a filament. 



Elongate, slightly compressed; depth everywhere a 

 little greater than the width. Head short, robust, its 

 greatest width 14 in its length; its width at the rictus 

 1|-1|; its depth at the base of the occipital process li-l|. 

 Bones of the skull covered with exceedingly thin skin, 

 their surfaces finely striate and granular; frontal bones 

 swoolen and deeply honeycombed. Frontal fontanel 

 open in front. Occipital process parabolic behind, firmly 

 joined to the dorsal plate. Dorsal plate emarginate be- 

 hind, sending two long, curved processes backward to 

 below the dorsal spine where they are curved downward 

 and slightly forward. Sutures distinct. 



Eye moderate, situated immediately above and behind 

 the angle of the mouth; its diameter 1 in snout, 4-4| in 

 head, 2^ in the interocular. 



Maxillary barbel reaching to the middle of the pectoral 

 or further; mental barbels little beyond base of pectorals, 

 postmentals inserted slightly posterior to the rictus and 

 extending about as far as the barbels of the maxillaries. 



Snout broad, rounded in front; jaws subequal, the 

 lower a little the shorter; teeth all villiform, those on the 

 intermaxillaries forming a curved band of uniform depth 

 throughout, its depth being about one-seventh of its 

 width. 



Gill-opening extending to base of pectoral. Gill-rakers 



