. CVIII. 287 



as. Teeth in the principal row 4 4 ; the barbel at the 



extremity of the maxillary. 



t. Teeth with developed grinding surface; dorsal 

 fin directly over ventrals ; scales large ; head 

 broad, much depressed, nearly flat above, re- 

 sembling the head of a Cyprinodont. 



PLATYGOBIO, 19. 



tt. Teeth without grinding surface ; dorsal fin be- 



ginning over, slightly before or slightly behind 



ventrals ; head not flattened. NOCOMIS, 20. 



rr. Premaxillaries not projectile, the skin of the lip 



continuous with that of the forehead ; teeth 2, 4 4, 



2, without grinding surface ; dorsal behind ventrals ; 



barbel terminal ; scales very small ; mouth more or 



less inferior. . . . RHIXICHTHYS, 21. 



ft Dentary bones straight and flat, united throughout their 



length; mandible much incurved, tongue-like, a lobe on 



each side of it at base ; air bladder normal ; bones of head 



not cavernous; intermaxillaries not projectile. (Exogloa- 



u. Teeth 1, 4 4, 1, hooked, without grinding surface ; dorsal 



slightly behind ventrals ; no barbels. EXOGLOSSOI. 22. 



** Species introduced from the Old World ; dorsal very long and 



anal short, each preceded by a stout spine which is serrated 



behind. 



0. Mouth without barbels teeth compressed, 4 4. (Carassiina.') 



CARASSIUS, 23. 



vo. Mouth with four long barbels; teeth molar 1, 3 3, 1, (Gy- 

 prinince) ....... CYPRINUS, 24. 



/. CAMPOSTOMA, Agassiz. STONE LUGGERS. 



1. C. anomala, (Raf.) Ag. STONE LUGGER. STOXE 

 ROLLER. Brownish, with a brassy luster above, the 

 scales more or less mottled with dark; a black vertical 

 bar behind opercle; iris usually orange-red; dorsal and 

 anal each with a dusky cross-bar about half way up, the 



