1906.1 



NATURAL SCIENCES OF PHILADELPHIA. 



437 



extremity reaching beyond front margin of orbit, but not till opposite 

 front margin of pupil. Mandible strong, protruding beyond tip of 

 upper jaw, and rami not elevated inside of mouth. Lips rather thin. 

 Teeth in jaws mostly quindentate, 4 on each side, in an outer series 

 above, and those forming mandibular series large and powerful. Max- 

 illary with 2 basal denticles. Tongue apparently flattened, a little 

 elongate and hardly free. Nostrils, as usual, in front of eye above. 

 Interorbital space moderate, and convex. Opercle deep, and upper 

 posterior edge emarginate. Greatest width of infraorbital rim 

 greater than greatest exposed breadth of opercle. 



Fig. 36. — Astyanax utahualpianus Fowler. 



Gill-opening extending forward about opposite posterior extremity 

 of maxillary. Rakers about 8 + 11?, lanceolate, and shorter than 

 filaments which are about y of orbit. Isthmus narrowly triangular. 



Scales mostly fallen, cycloid, each with several striae, thin, large, not 

 narrowly imbricated, and apparently disposed in longitudinal series 

 parallel with lateral line. Base of anal apparently with a low sheath 

 of small scales. Base of caudal also covered with small scales. Lateral 

 line apparently as usual or a little decurved, then sloping up to base of 

 caudal, though a little low at first along side of caudal peduncle. 

 Tubes simple. 



Origin of dorsal much nearer base of caudal than tip of mandible 



