286 CALIFORNIA ACADEMY OF SCIENCES. 



Barbels six, mental barbels disposed in two pairs. 

 Teeth villiform, none on the vomer or palate. Eye 

 large, lateral, covered with skin. Adipose fin very short. 

 Dorsal fin with a spine and six rays. Anal rather long, 

 emarginate, the anterior rays in the male elongate bear- 

 ing the urogenital tube. Ventral fins free, of eight 

 rays. Pectoral spine strong, serrated on its inner mar- 

 gin; humeral process large. Occipital process firmly 

 joined to the dorsal plate. Gill-membranes confluent 

 with the skin of the isthmus. Bones of the head thick, 

 mostly covered with skin. Head narrow, compressed, 

 strongly convex transversely, its depth equal to or greater 

 than its width. Pectoral pore present. 



Habitat: Mouths of rivers from Jequitmhoiiha to 

 Guiana. 



ANALYSIS OF THE SPECIES OF FELICHTHYS. 



a. Frontal bones not swollen or honeycomb-like; postorbital portion of 

 the head covered with loose skin. 

 b. Sides of body immaculate; upper caudal lobe dusky. 



c. Mental barbels about as long as diameter of eye; snout somewhat 

 pointed, its greatest width less than half length of head; humeral 

 process smooth. jequitinhonhw 227. 



cc. Mental barbels reaching base of pectoral; snout bluntish, its 

 greatest width 2 in the head; dorsal surface brown, a triangular 

 spot behind eye and the opercle yellow; sides and ventral surface 

 yellow; upper caudal lobe dusky, otherwise fins plain (in spirits). 



flavescens 228. 



bb. Sides of body thickly covered with brown dots, caudal dusky; men- 

 tal barbels reaching about to base of pectoral; width of snout If in 

 head. (/jtiti/* -Ji'!). 



aa. Frontal bones swollen and of honeycomb structure; postorbital por- 

 tion of head granular, covered with very thin skin nodosus 230. 



227- Felichthys jequitinhonhse, 



Auchenipterus jequitinhonhce Steindachner, SB. Ak. Wieu, Ixxiv, 

 1876, Siisswasserfische Siidostl. Bras, iii, 89, pi. vi, fig. 1, la 

 (Kio Jequitinhonha). 



Felichthys jequitinhonhce Eigenm. & Eigenm. Proc. Cal. Acad. 2d 

 Ser. i, 152, 1888 (Jequitinhonha). 



Habitat: Jequitinhonha. 



