78 THE WASATCH AND BRIDGER FAUNiE. 



behind the origin of the dorsal. The formulae for the D. humilis are as fol- 

 lows:— Radii: D.I— 11; A. I— 14. Vertebrtv: D. 21; C. 13. Depth to 

 length as 3 : 8. 5. 



Specimens of this fish are equally abundant at the Green River and 

 Twin Creek localities. A rather small specimen from the former place was 

 described by me as the type of another species, but I think it represents 

 merely a young individual. When I described it I was under the impres- 

 sion that the D. alius was the true D. humilis of I.,eidy. This view was 

 justified by Dr. Leidy's description of the D. humilis, where the measure- 

 ments given are those of the B. alius. The figures given (3J inches long 

 by 16 lines deep) are, however, partly erroneous, as they do not agree with 

 those subsequently given, nor with the plate above cited. The description 

 of a Green River specimen is as follows: 



Greatest depth contained four times in the total length or 3.5 times to 

 basis of caudal fin. Length of head 3.2 to basis caudal. This measure- 

 ment may require revision, as the end of the muzzle is slightly injured. 

 Orbit large, contained twice in length of head behind it. Middle of dorsal 

 fin near the middle of the length, and about over the origins of the ventrals. 

 D. II, 1 1, V. 7. Pectoral extending half way to ventrals. Vertebrae, 2!)-30; 

 dorsals, 16-20. Ventral keeled ribs, 18. Anal fin lost. Caudal peduncle 

 slender caudal fin deeply furcate. Length, ".044; greatest depth, "Oil. 



A second specimen exhibits the characters of the species more dis- 

 tinctly in some respects. There are 30 vertebrae, of which 13-14 are caudaL 

 The general shape is regularly fusiform, and the head rather acuminate. ' 



Measurements. 



H. 



Total length 054 



Lc;nj;th to preopercnlar edge 01 



Li'iinlli to opercular edge 013 



L«iiglli to posterior margin dorsal (H55 



Length to anterior margin anal .034 



Length to Iibho lauilal 044 



Depth at oroiput .011 



Dejith at middle of dorsal 0116 



Depth nt caadal peduncle '. 0046 



The largest specimen of this species which I possess is "150 in 

 length. 



