40 Field Columbian Museum — Zoology, Vol. V. 



qq. Scales larger, 30 to 45 in the lateral page 



series; less than 20 scales between 

 nape and dorsal fin; teeth 4-4 in 

 the main row, occasionally one or 



two in smaller row Nototropis 62 



00. Lower jaw with the lip developed as 

 a fleshy lobe on each side ; teeth 4-4 ; 



scales 43 to 45 Pin nacobius 76 



mm. Scales small, 80 to 100 in the lateral 

 series ; body long and slender, subterete ; 

 mouth small, the upper jaw little pro- 

 tractile; teeth 4-4 Evarra 77 



11. Maxillary with a small barbel at or near its 

 extremity, 

 r. Premaxillaries not protractile, the frenum 

 very broad; teeth 2, 4-4, 2 or 1; scales 



small, 60 in the lateral series Rhinichthys 79 



rr. Premaxillaries protractile, rarely joined 

 to the forehead by a narrow frenum. 

 s. Scales very small, 60 to go in the 

 lateral series; lateral line often incom- 

 plete; dorsal fin posterior \gosia 79 



ss. Scales large, 35 to 55 in the lateral 

 series; dorsal median; lateral line com- 

 plete, 

 t. Teeth 4-4, or 1,4-4, 1 or o; the lesser 

 row with never more than one; scales 



35 to 45 Hybopsis 80 



tt. Teeth 2, 4-4, 2 or 1 ; scales more 



than 50 in the lateral series CoueStus 82 



aa. Dorsal fin short, posterior, with a strong spine; 

 body without scales; teeth 2, 4-4, 2; maxillary 

 with a barbel Plagopterus S3 



Subfamily Campostomatinse. 



14. Campostoma Agassiz. 



Campostoma Agassiz, Amer. Jour. Sci. Arts, 1855, 218. (Type, Rit- 

 tilus anomalus Rafinesque.) 



Body moderately elongate, little compressed; mouth rather small, 

 the jaws with thick lips and the rudiment of a hard sheath; premaxil- 

 laries protractile; no barbel; pharyngeal teeth 4-4, or 1, 4-4, o, with 

 oblique grinding surface, and a slight hook on one or two teeth; air 



