86 VERTEBRATE ANIMALS OF THE UNITED STATES 



scales small; dorsal fin behind the ventrals; coloration dark; males rosy 

 in the spring: 3 species, i in Mexico. 



Keys to the United States Species of Rhinichthys 



ai Snout projecting far beyond the mouth R. calaractce. 



ao Snout projecting but little beyond the mouth R. atronasus. 



R. cataractce (Cuvier & Valenciennes). Long nosed dace. Length 

 125 mm.; head 4; depth 5 to 5.5; color dark olive, paler below; back 

 almost black; a dark spot on the opercle; body elongate; head long; 

 mouth inferior; rays of dorsal fin 8; anal 7; scales 65: New England 

 to the Columbia; southward to North Carolina and the Great Salt 

 Lake basin; in swift streams; common and variable. 



Subspecies of R. cataractce 



R. c. cataractce (C. & V.) . New England to Wisconsin. 

 R. c. dulcis (Girard). Scales 11 or 12-63 to 70-9 to 12; a dark 

 lateral band: Rocky Mountain region. 



R. atronasus (Mitchill). Black nosed dace. Length 75 mm.; head 

 4; depth 4.5; color blackish, with a black lateral band; males in spring 

 with the lateral band, lower fins and sometimes the whole body crimson, 

 the lateral band in late summer becoming orange and later getting dark; 

 rays of dorsal fin 7; anal 7; scales 64; teeth 2, 4-4, 2: New England to 

 Minnesota; southward to Alabama; very common in clear brooks; 

 very variable. 



Subspecies of R. atronasus 



R. a. croceus (Storer). Rays of anal fin 6; scales 70; lateral band 

 faint brownish: Tennessee basin; common. 



R. a. lunatus Cope. Similar to R. a. croceus; lateral band obsolete; 

 scales 62: Michigan and Indiana; common. 



27. Agosia Girard. Similar to Rhinichthys except that the pre- 

 maxillaries are protractile; rays of dorsal fin mostly 8; anal 7 : 10 species, 

 all in the Rocky Mountain region. 



Key to the Species of Agosia 



ai Teeth i, 4-4, i. 



bi Dorsal fin with 8 rays. 



Ci Scales small, more than 70 in the lateral line. 



di Scales about 89 A. oscula. 



d2 Scales about 78 A. yarrowi. 



