1911.] 



NATURAL SCIENCES OF PHILADELPHIA. 



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edge. Lips rather thin, mandibular little better developed. Teeth 

 only in jaws, well compressed, imiserial, all with tips slightly inclined 

 inward, each tooth triangular with broad base and slight cusp each 

 side, these becoming obsolete only on posterior teeth. Cutting-edges 

 of teeth mostly with at least obsolete or feeble minute seme, usually 

 better developed towards basal cusps when present. Mandibular 

 teeth considerably larger than upper ones. Buccal fold inside mouth 

 along each row of teeth, large and fleshy. Tongue depressed, surface 



Fig. 4. — Serrasalmus coccogenis Fowler. Type. 



level, rather pointed, and free in front with rounded tip. Mandible 

 well protruding, moderate, strong, surface rather well convex below, 

 and rami little elevated in mouth, though much deeper at posterior 

 articulation than at symphysis. Nostrils large, together, both as 

 simple large pores with broad cutaneous flap of anterior exposing 

 posterior in crescent. Interorbital broadly and evenly convex. 

 Infraorbital width If in eye, with narrow preorbital anterior pro- 

 jection. Postero-infraorbital width about If in eye, though not 

 extending below to preopercle ridge, leaving an elongated and somewhat 

 crescentic naked region on cheek below, greatest width of latter about 



