268 CTPKINID^, 



than the length of the head, which is somewhat less than one-fifth 

 of the total (without caudal). Eye small, one-seventh of the length 

 of the head. Snout depressed and produced, the upper jaw over- 

 lapping the lower ; mouth horizontal, the maxillary extending 

 nearly to the vertical from the front margin of the orbit. Origin of 

 the dorsal fin somewhat in advance of that of the ventrals, and much 

 nearer to the end of the snout than to the root of the caudal. Cau- 

 dal lobes equally developed. Upper pectoral ray produced ; ventral 

 fins reaching the anus. Coloration uniform. (Girard.) 



Milk River ; Platte River ; Nebraska ; Yellowstone River. 



4. Leucosomus gulonellus. 



Pogonichthvs (Platygobio) gulonellus, Cope, Proc. Ac. Nat, ISc. Philad. 

 1804, p. 277. 



D. 9. A. 9. V. 9. L. lat. 48. L. transv. 7/?. 



The length of the head is two-ninths of the total, to the end of 

 the middle caudal rays ; the diameter of the eye is contained five 

 times ard two-thirds in the length of the head. Origin of the 

 dorsal fin much nearer to the end of the snout than to the root of 

 the caudal. Ventral fins truncate, terminating at a great disilince 

 from the vent. There are five longitudinal series of scales between 

 the lateral line and ventral fin. A faint longitudinal dark band on 

 one row of scales above the lateral line. {Cope.) 



Bridge r's Pass. Six inches long. 



5. Leucosomus pulchellus. 



Leuciscus argenteus, Stover, Rep. Fish. Massach. p. 90 (young). 



pulchellus, Storer, I. c. p. 91 (adult) ; Dekay, Neiv Yoi-k Faun. 



i^jsA. p. 208; ? C?/y. ^ Ta/. xvii. p. 320. 

 Leucosomus argenteus, Meckel, in Ktissegger'' s Reis. i. p. 1043 (name 



only). 

 Leuciscus nitidus, Dekay, I. c. p. 209, pi. 33. fig. 105, 

 ? Leuciscus chrysopterus, Dekay, I. c. p. 211, pi. 30. tig. 95. 

 Leuciscus storeri, Cuv. ^ Val. xvii. p. 319, pi. 505. 

 Cheilonemus pulchellus, Storer, Mem. Am. Acad. v. 1855, p. 286, 



pi. 22. fig. 2. 

 Leucosomus pulchellus, Girard, Proc. Ac. Nat. Sc. Philad. 1866, 



p. 189. 

 Hybognathus nitidus, Girard, I. c. p. 210. 

 Semotilus corooralis, Abbott, ibid. 1861, p. 154. 

 Leucosomus rnotheus, Cope, ibid. p. 523. 

 Squalius hyalope. Cope, ibid. 1864, p. 280. 



Semotilus rhotlieus, Cope, Journ. Ac. Nat. Sc. Philad. xiii. p. 362, 

 pi. 10. fig. 1. 

 D. 10. A. 10. V. 0, L. lat. 45-48. L. transv. 7|/7. Vert. 25/19. 

 The height of the body is somewhat less than the length of the 

 head, and nearly one-fourth of the total (without caudal). Head 

 two-thirds as deep as long. The diameter of the eye is one-fifth of 

 the length of the head in half-grown examples, and nearly one- 

 seventh in adult. The width of the inierorbital space, which is 



