JORDAN ON FISHES OF DAKOTA AND MONTANA. 787 



7c. Maxillary without barbel. 



I, Anal basis considerably elougate (of 12 to 25, rarely fewer, 



rays) ; belly behind ventrals compressed to an 

 edge; lateral line decurved, complete, 

 m. Teeth 5-.5, sharp pointed, with grinding surface ; anal rays 



11 to 15 KOTEMIGONUS. 



mm. Teeth 2,5-5,2, entire, without grinding surface; anal rays 

 13 to 30 Alburnus.* 



II. Anal basis shorter (of 7 to 11 rays) ; abdomen not compressed 



to an edge. 

 n. Teeth 1, 3-3, 1, without grinding surface; dorsal behind ven- 

 trals; isthmus very wide Tiaroga. 



nn. Teeth in the main row 4-4. 

 0. Opercular and mandibular bones, without externally visi- 

 ble cavernous chambers. 

 p. Teeth with grinding turface developed. 



q. Jaws with a hard, bony sheath, resembling the teeth of 

 Tetrodon ; teeth 4-4 ; rudimentary dorsal ray con- 

 nected by membrane Cochlognathus. 



qq. Jaws normal ; rudimentary dorsal ray attached. 

 }•. Teeth 4-4 or 1, 4-4, 1 ; anal basis short (rays 7 to 9). 



8. Scales very small Algansea. 



ss. Scales large. 



t. Lateral line complete Hudsonius. 



tt. Lateral line incomplete CHRiOPE.t 



rr. Teeth 2, 4-4, 2. 

 u. Dorsal fin over or slightly behind ventrals ; anal 



basis short (8 or 9 rays) LuxiLUS. 



uu. Dorsal fin much behind ventrals; anal basis 



elongate (10 to 12 rays) Lythrurus. 



pp. Teeth without masticatory surface, their edges serrate 

 or entire. 

 V. Lips thin, normal ; lateral line complete. 



tv. Teeth 2, 4-4, 2 Notropis. 



wiv. Teeth 4-4 or 1, 4-4, 1 Cliola. 



vv. Lips thin ; lateral line incomplete; teeth 1, 4-4, 2. 



Peotoporus. 

 vvv. Lips thick, fleshy, enlarged behind; mouth small, in- 

 ferior ; dorsal tin beginning in front of ventrals ; 

 teeth 4-4; lateral line complete ..Phenacobius. 

 00. Opercular and mandibulary bones with externally visible 

 cavernous chambers ; teeth 1, 4-4, 0, without 

 grinding surface ; lips normal ; dorsal over ven- 

 trals Ertcymba. 



nnn. Teeth in the main row 5-5 or 5-4. 

 A. Lateral line incomplete. 



B. Dorsal fin over ventrals ; scales large ; teeth 4-5, with 



grinding surface Hemitremia. 



BB. Dorsal fin behind ventrals ; scales small ; teeth 2, 5-5, 2 

 (or 2, 5-4, 2), without grinding surface. Phoxinus. 

 AA. Lateral line complete. 



C. Teeth raptatorial, entire, without grinding surface, 2, 



5-4 or 5, 2 or 1. 



* Alburnus Heckel =: Bichardsonius Grd. 



iChriope, gen. nov. ; type Hyiopsis Mfrenatus Cope. 



