230 Bulletin 47, United States National Museum. 



c. Caudal peduncle very deep and compressed, its least depth nearly equal to depth of 

 head; dorsal inserted above ventrals; scales comparatively large and well imbricated, 

 about 56. JRASSICAUDA, 363. 



TIGOMA, (a coined name): 

 cc. Caudal peduncle not very stout, its least depth not % depth of head ; scales jmall, 



not closely imbricated ; dorsal usually inserted behind ventrals. 

 d. Scales of medium size, 50 to 75 in the lateral line ; young with the head more 



or less conical ; adults with the head flattened and the back elevated. 

 e. Species from the Sacramento Basin ; scales large, about 52. 



CONFORMIS, 364. 



ee. Spcies from the great basins of Utah, Nevada, Idaho, and Oregon; scales 



rather large, 53 to 63. 



/. Sides of body abruptly silvery from a line just above lateral line; scales 



13-60-7. BICOLOR, 365. 



ff. Sides of body scarcely silvery, the scales everywhere much dotted; head 



subconical; eye small; form extremely variable. LINEATUS, 366. 



eee. Species from the basin of the Kio Grande; mouth large; head large; teeth 



extremely variable; scales 60 to 67. NIGRESCENS, 367. 



eeee. Species from the basin of Rio Yaqui ; scales 62 ; body robust. 



PURPUREUS, 368. 



eeeee. Species from the Gila basin ; head more blunt ; scales 73 to 75 ; body 

 rather elongate. INTERMEDIUS, 369. 



dd. Scales very small, 80 in the lateral line. 



g. Head depressed above; back elevated with age; species of large size; 



from the Gila Basin. NIGER, 370. 



gg. Head not depressed ; the back not elevated ; species of small size, from 



the Great Basin of Utah. ALICI/K, 371. 



bb. Anal basis long, of 9 to 22 rays, the fins all high; body more or less compressed; 



head bluntish, with large eye ; scales moderate, not closely imbricated, 55 to 65 in 



lateral line. 



CHEONDA, (a coined name): 

 h. Anal rays 9 to 13, usually 11. 



t. Coloration plain ; body not much compressed. COOPERI, 372. 



ti. Coloration not plain ; sides with a dark lateral band, or with two dark bands ; the 



interspace and the belly bright red in spring males. 



j. Body very deep, the depth 3 in length. HUMBOLDTI, 373. 



jj. Body moderately elongate, the depth 4 to 4% in length ; cheek with a silvery or 



golden crescent ; a pale streak from gill opening above eye. 



k. Anal rays usually 9 or 10 ; two dark lateral stripes. EGREGIUS, 374. 



Ttk. Anal rays usually 11 or 12 ; one dark lateral stripe, forking anteriorly. 



HYDROPHLOX, 375. 



RICHARDSON ITJS, (named for Sir John Richardson): 



hh. Anal rays 14 to 22, usually 16 ; body much compressed ; a dark lateral stripe ; crescent 

 on cheek very distinct. BALTEATUS, 370. 



CLINOSTOMUS, (*A.iVw, to incline ; orojua, mouth): 



aa. Mouth very wide, the lower jaw much projecting beyond upper ; upper-lip on the level of 

 the middle of the pupil ; maxillary reaching to below the pupil ; body elongate, com- 

 pressed ; dorsal well back ; males with red pigment, often brilliantly colored. 



I. Scales moderate, 50 to 55 in lateral line. VANDOISTTLUS, 377. 



II. Scales minute, 63 to 70 in lateral line. ELONGATUS, 378. 

 II. Lateral line more or less incomplete ; small species, the males usually brilliantly colored, 



the sides and belly red in spring. 

 PHOXINUS, ((/>oivos, minnow; from $od?, tapering; the old name of the European "minnow," 



Lenciscus phoxinus): 

 m. Scales minute, 80 to 100 in a longitudinal series ; lateral line very short ; snout blunt. 



NEOG^EUS, 379. 



HEMITREMIA, (TJJU-, half; Tprj/ua, aperture = lateral line) : 



mm. Scales moderate or large, 40 to 60 in a longitudinal series ; lateral line variously devel- 

 oped, sometimes almost complete. 



