1015. 



NATURAL SCIENCES OF PHILADELPHIA. 



265 



at ends, bifid, 44 in upper jaw and 47 in lower jaw, one of bifurcations 

 always shorter and smaller than other. Inner buccal folds rather 

 wide. Tongue broad and fleshy. Each lateral corner of buccal 

 disk with slender barbel about equal to eye in length. Nostrils 

 large, together, dividing frenuni falls little before last fourth in 

 .snout length, socket much less than that of eye, and both fall within 

 confines of internasal space. Anterior nostril simple pore with 



Fig. 3. — Plecostomus jaguribensis fowler. (Ty 



pe.) 



cutaneous flap behind forming valve completely covering slightly 

 larger posterior nostril. Interorbital rather wide, double concave, 

 due to slightly elevated supraoccipital median ridge and each supra- 

 orbital also being little elevated. Hind edge of occipital ridge 

 broadly triangular. Opercle large, moderately porous. 



Gill-opening small, lateral, oblique, and extends forward about 

 opposite first third in eye. Isthmus broad, about lyV ii^ snout. 



