peduncle. Inferior fins reddish. The more anterior position of the 

 dorsal lin is one point of difference from E. maxillosus. 



From Provo ; No. 48, a. 



Var. II, back dark ; a dark band from end of muzzle to caudal fin. Fins 

 and lips red. D. I. 8 Provo ; 204 a ; 281 a ; Colorado Chiquito, 5x., 240 

 Twin Lake, Colorado. Var. III. Back dusky ; numerous large black 

 spots all over the sides and head; fins and lips crimson, D. I. 8, 

 No. 754, from Apache, Arizona. 



TIMPANOGENSIS, Sp. 11OV. 



A rather compressed species with mouth obliquely descending, and 

 teeth 2.4 4.2, with strongly developed masticatory surfaces. The lateral 

 line of tubules is imperfect in all the specimens, often only repre- 

 resented by a short series in front of the dorsal fin. In larger specimens 

 it is better developed, and in still larger it may be complete, a point 

 which remains as yet uncertain. In the smaller specimens of Myloleucus 

 parovanus, the series is imperfect for a short distance in front of the 

 caudal fin, while it is complete in adults. I have observed the same in 

 the Ilypsilepis anolostanus, Girard. Scales small 11. The dorsal fin 



6 



originates a little in front of a line drawn from the base of the first ven- 

 tral ray. I'he pectorals do not reach the ventrals, while the latter attain 

 the vent. Radii D. I. 9 ; A. I. 8 ; V. 8. 



The depth is one-fourth the length, less that of the caudal fin, and the 

 length of the head enters the same 3.66 times. Orbit 3 3 times in length 

 of head, 1.2 times in interorbital width ; longer than muzzle. Preorbital 

 bone trapezoid. Total length M .047 ; do. to basis of dorsal .0315 ; of 

 head .011 ; width at pterotics .005. 



There is a narrow leaden line from the pterotic region to the base of 

 the caudal, below which the color is yellowish, and above brownish, all 

 dusted with black points. Cheeks silvery. Fins dusky. 



Numerous specimens were taken at Provo by Messrs. Yarrow & Hen- 

 shaw, and at Guunison (No. 668) by Mr. Klett. 



MlNOMUS PLATYRHYNCHUS, Sp. DOT. 



This Catostomoid belongs to the genus Minomus, Girard, as defined by 

 the writer in Hayden's Annual Report of the U. S. Geological Survey for 

 1870, p. 434. It is of very elongate form, the depth of the body at the 

 dorsal fin entering the total length seven and two-fifths times. The head 

 is short and wide, with expanded and depressed muzzle ; its length en- 

 ters the total five and three-quarter times. The scales are materially 

 larger on the caudal peduncle than on the post-scapular region, and the 

 dorsal fin originates considerably nearer the end of the muzzle than the 

 basis of the caudal fin. Radial formula, D. I. 11 ; C. 18, openly emar- 

 ginate ; A. I. 7 ; V. 9 not reaching vent ; pectoral reaching half-w ty to 

 ventral. Scales it. The orbits are excavated at their superciliary border, 



