44 
BULLETIN OF THE UNITED STATES FISH COMMISSION. 
spots, opercles silvery with orange washing and a few dark spots; ventral fins yellow, 
pectorals a little less so, anal same as ventrals ; dorsal and caudal darkish or muddy 
yellow; maxillaries and tip of lower jaw with fine dark punctulations. 
Younger individuals are essentially the same in color, only that the fins and 
posterior parts of the body are not so yellow and in the youngest there is a dark blotch 
at base of caudal fin. 
8. Leuciscus hydrophlox (Cope). (PL xx.) 
This species was very abundant in Snake River at President Gamp, Wyoming, 
where eighty-three specimens were obtained ; also in the small creek at the head of 
Jackson Lake. The specimens are 3 inches or less in length. Dorsal rays 9 in numer- 
ous specimens counted ; anal usually 12, 11 in some examples ; base of fin 6J in length 
of body; maxillary barely reaching orbit, lower jaw somewhat projecting; dark band 
on side continued forward over the opercle; lateral line less decurved than in Heart 
Lake specimens. 
9. Leuciscus gilli, sp. nov. (Types No. 43953, U. S. Nat. Mus.) (PI. xx.) 
This species is based upon fourteen specimens, 3 to 4^ inches long, taken in 
Browns Gulch Creek, at Silver Bow, Montana, July 27, 1891. Head, 4 to 4j in length 
to base of caudal; depth, 34 to 3,f ; eye, 34 to 4 in head, 14 in interorbital width; snout, 
3£ to 3§; D. 10 (occasionally 9 or 11); A. 14 (13, 15, or 16 in a few specimens); 
scales, 11-66-7 ; teeth, 2, 5-4, 2. Body compressed, deep, back little arched, ventral 
line considerably curved, bending gently upward at beginning of anal fin ; head heavy, 
snout short and blunt, lower jaw not projecting, mouth oblique, maxillary not quite 
reaching front of orbit; caudal peduncle long and slender; scales moderate, deeper 
than long on anterior part of body, but longer than deep on caudal peduncle, about 
32 before the dorsal. Dorsal fin small, much nearer caudal fin than snout, about mid- 
way between beginning of scaled surface at back of head and beginning of rudi- 
mentary caudal rays, its origin behind vertical line from ventrals a distance equal to 
the length of its base; base of dorsal fin If in its height, which in turn is Lj- in head; 
its free margin falcate. Anal fin large, its base about 5g in length of body to base of 
caudal fin, or about equal to length of pectoral; longest rays a little shorter than 
length of fin; free margin very nearly straight; origin of fin under last fifth of dorsal; 
ventrals short, 14 in head, reaching vent in some specimens; pectorals long, 14 in head, 
nearly reaching ventrals in some examples; caudal fin very long and deeply forked, 
lower lobe the longer, 4^ in total length. 
Color in alcohol, upper parts dark down to level of eye; beginning at upper level 
of eye is a band about one scale in width that is chrome yellow on head, then widening 
slightly and becoming rosy until the middle of the side is reached, where it becomes 
gradually less distinct until hardly discernible on the caudal peduncle; below this is 
a dark band about twice as wide, the middle portion of which lies just above the lateral 
line, but at each end it extends a little below; side of body below lateral line rich 
rosy with tinge of yellow, whitening on the caudal peduncle ; orange at base of ventrals 
and pectorals, the latter with some reddish ; belly white ; cheek with a large crescent 
of chrome yellow, very bright in some specimens, extending from angle of mouth 
across the cheek and up back of the eye, nearly connecting with the line first described ; 
opercles silvery, with some little orange washing, covered over with many fine black 
punctulations, most numerous above, where they form a large dark blotch ; whole body 
