PLECTOSPONDYLI CYPK1NIDAE GILA MONTANA. 657 



Gila nigra, Cope. 



Gila egregia, Girard (Tigoma). 



Gila nacrea, Cope. 



Gila semimida, Cope and Yarrow. 



Gila gracilis, Baird and Girard. 



Gila grahamii, Baird and Girard. 



Gila clegaiis, Baird and Girard. 



Gila robttsta, Baird and Girard. 



GILA PHLEGETHONTIS, Cope. 

 PLATE XXVII, FIGS. 4, 4a. 



Clinostomus phlegethontis, COPE, Proc. Am. Phil. Soc. Pbila., 1874, 137. Id., Kep. Plagop. 

 & Ichtby. Utab, 1874, 11. 



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 without 

 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 0.2 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. 1. 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, (T.034; length to basis of dorsal, O m .0186 ; length of head, O m .008 ; 

 width of head -at pterotics, O m .0038. A broad plumbeous band on the 

 side, below which the color is golden, above it is probably translucent in 

 life, with a dusky median dorsal line. 



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

 Dr. H. C. Yarrow and H. W. Henshaw; abundant. 



GILA MONTANA, Cope. 



Clinostomus montamis, COPE, U. S. Geol. Snrv. Montana & Adjacent Territories, 1871, 

 47C. Id, Proc. Am. Pbil. Soc. Phila., 1874, 130. Id, Eep. Plagop. & Ichtby. 

 Utah, 1874, 10. 



Muzzle decurved, obtuse ; jaws equal ; end of maxillary extending 

 42 \ 



