12 FISHES OF THE YELLOWSTONE NATIONAL PARK. 



aa x . Dorsal fin single, the fully developed rays all soft and jointed. 



c'. Mouth wholly inferior with thick papillose lips, especially the lower lip. 

 d f ' . Scales in lengthwise series very small, reduced and crowded anteriorly, 

 90 to 110. Snout long. Coloration dusky brown, sometimes \vith a 



broad red flush or irregular stripe Longnose sucker, 12. 



dd' ' . Scales in lengthwise series 70 to 72, not particularly reduced or crowded 



anteriorly. Snout not long. Coloration blackish above, males with 



more or less rosy flush or stripe in breeding season . . Rosyside sucker, 13. 



cc 7 . Mouth more or less terminal or oblique, sometimes slightly inferior, but lips 



never thick or papillose. 

 e f . Mouth oblique. 



/'. Anal rays 8; scales in lengthwise series 55 to 63;- mouth very oblique 

 lower jaw somewhat projecting. Coloration blackish, everywhere 

 dark; scales much dotted and with dark edges; often forming lines 



along the rows of scales. Males without red Chub, 14. 



ff / . Anal fin rays 10 to 13, usually 10 or 11; scales about 58, mouth 

 oblique, short, jaws about equal. Coloration greenish silvery; 

 the back dusky; a dark blue or blackish lateral band between two 

 silvery stripes; the lateral band and below bright orange-red in 

 the males, the red usually ceasing at front of anal ; a bright silvery 

 or golden crescent on chubs; a golden streak from snout above eye 

 to gill opening. Very pale in alkaline waters. 



Silverside minnow, 15. 

 eef . Mouth subinferior. 



g' . Tipper jaw not protractile, the upper lip continuous with the skin 

 of the forehead, muzzle long and projecting, color silvery, darker 

 above; a dusky lateral shade most distinct in young, males largely 



rosy Longnose dace, 16. 



gg / . Upper jaw protractile, i. e., the upper lip capable of being drawn 

 out from the snout; muzzle not particularly long. Color usually 

 dark grayish above becoming paler below, a faint lateral band 

 of dark extending through the eye and around snout. 



Dusky dace, 17. 



1. MONTANA GRAYLING ( Thymallus montanus} . 



The Montana grayling originally existed only in tributaries of the 

 Missouri River above Great Falls. 



In the park it occurs naturally in Madison and Gallatin Rivers and 

 branches, Fan Creek, Grayling Creek, and the Firehole River below 

 the falls. It is reported as very abundant at the junction of Firehole 

 and Gibbon Rivers. It is said to ascend, in summer, as far as Fire- 

 hole Falls and to be found in the Gallatin River in the northwestern 

 part of the park. 



The Montana grayling is a most graceful and beautiful fish, of 

 shapely proportions and exquisite coloration. The adult averages 

 from 10 to 12 inches in length and from about J to 1 pound in weight. 



It prefers swift, clear, pure streams, with gravelly or sandy bottom. 

 It is quite gregarious, lying in schools in the deeper pools, in plain 

 sight, and not, like the trout, concealed under bushes and overhang- 

 ing banks. In search of food, which consists principally of bisects 



