18U.] ^^i [Cope. 



well as by the reduced number of radii of the anal fin. The genus 

 Myloleucus was established by the writer in 1871* for species resembling 

 Siboma, in having the pharyngeal teeth of the longer row 4 — 5, and the 

 origin of the dorsal fin situated in advance of the ventral, but differing in 

 the possession of well-defined masticatory surfaces on the teeth. The 

 typical species is M. pulverulentus, Cope, from the warm springs of Utah, 

 a fish which differs from the present one in the greater stoutness of form 

 and smaller and more numerous scales. 



Form moderately stout ; muzzle short, conical, lips even, mouth very 

 oblique, maxillary bone reaching anterior line of orbit. Profile of head 

 and back gently arched. Depth of body equal length of caudal fin and 

 measxiring 4.25 in the total length less that fin ; length of head, 3.5 or 6 

 in the same. Orbit large 3.1 times in length of head; greater than muzzle, 

 equal interorbital width. Scales u, the lateral line decurved in front, 

 and continued to base of caudal fin. Radii, D. I. 9 ; A. I. 8 ; Y. 9. The 

 pectorals reach little more than half way to the ventrals ; the latter just 

 attain the vent. Caudal well forked. The color is transparent, with a 

 plumbeous lateral band, the ventral and pectoral fins dusky, the dorsal 

 and caudal shaded with the same. Total length M. 0648 ; ditto to base 

 caudal, .053 ; ditto to anal, .038 ; to ventral, .0288 ; of head, .014 ; to 

 orbit, .003 ; width at middle pterotics, .0064. 



Numerous specimens were obtained by Dr. Yarrow from Beaver River, 

 in Southwestern Utah. This stream flows into the Sevier Lake, a very 

 alkaline body of water, in which no fishes were found by the naturalists 

 of the survey. 



Clinostomus phlegethontis, sp. nov. 



Teeth, 1.5 — 4.2 ; body, deep, short ; scales larger than in any other 

 species of the genus, viz.: eleven longitudinal and thirty-seven transverse 

 series. There is no lateral line, which may be due to the immature state 

 of the only specimen at my disposal. The depth enters the length with- 

 out the caudal fin 3.5 times, while the length of the head is counted in 

 the same four times. The orbit is large, entering the head 2.75 times, 

 and .2 greater than interorbital width ; in older fishes the orbit will be 

 found as usual relatively smaller. The lips are even, and the mouth 

 quite oblique, the end of the maxillary reaching the line of the orbit. 

 Radii, D. I. 7 ; A.I. 8 ; the ventrals originate in front of the line of the 

 dorsal, and extend to the vent, and are not nearly reached by the 

 pectorals. Length without caudal fin, .034 ; ditto to basis of dorsal, 

 .0186 ; length of head, .008 ; width ditto at pterotics, .0038. A broad 

 plumbeous band on the side, below which the color is golden, above it 

 probably translucent in life, with a dusky median dorsal line. 



Discovered in Beaver River, Utah, with the Myloleucus parovanus, by 

 Dr. Yarrow. 



* In Hayden's annual Report of the U. S. Geological Survey, p. 475. 

 A. P. S. — VOL. XIV. R 



