670 



ZOOLOGY FISHES. 



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 meas- 

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



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



n 



interorbital width. Scales, ; the lateral line decurved in front, and con- 

 tinued to base of caudal fin. Radii: D. I. 9 ; A. I. 8 ; V. 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, O m .0648 ; length to base caudal, O m .053 ; 

 to anal, CT.03S ; to ventral, O m .0288 ; length of head, O m .014 ; length to 

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



Numerous specimens were obtained by Dr.H.C. Yarrow and H. W. Hen- 

 shaw 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. 



The two species indicated are thus far the only ones of the genus 

 known. 



HYBORHYNCHUS, Agass. 



BYBORHYNCHUS SIDERIUS, Cope, sp. nov. 



PLATE XXXI, FIGS. 6, 6a. 



A fusiform species with a rather small acuminate head and with small 

 scales. The physiognomy is quite distinct from that of the known species 

 of this genus, resembling rather an Apocope. The teeth are of typical 

 character, and the intestines are very elongate, and the peritoneum black. 



