43. RniNICHTHYS. 1.80 



spine, not in advance of the ventrals. Anal fin short. Month inferior ; 

 intermaxillaries not protractile, their upper middle margin being 

 continuous with the skin of the upper part of the snout ; the labial 

 fold of the lower lip is lateral only, not extending across the sym- 

 physis ; no barbel, or only a rudimentary one at the angle of the 

 mouth, quite at the extremity of the maxillary. Gill-rakers very 

 short, and few in number ; pseudobranchise. Pharyngeal teeth unci- 

 nate, 4 . 1 — 2 . 4. 

 North America. 



1. Rhinichthys nasutus. 



Leuciscus nasutus, Ayres, Bost. Journ. Nat. Hist. iv. p. 299, pi. 13 • 

 fig. 3 (one of the best descriptions in American ichthyological 

 literature) ; Storer, Mem. Amer. Acad. v. 1855, p. 289, pi. 22. f. 1. 



Rhinichthys nasutus, Agnsdz, I. c. (name only). 



ArgjTeus nasutus, Cope, Journ. Acad. Nat. Sc. Philad. xiii. p. 3G9, 

 pi. 12. fig. 5. 



D. 10. A. 8. L. lat. 65. L. transv. 14/18. 



Barbel minute. The eye is half as long as the snout, and occupies 

 the middle of the length of the head. Snout projecting beyond the 

 mouth. The height of the body is contained five times in the total 

 length ("without caudal), the length of the head thrice and four- 

 fifths. The origin of the dorsal fin is a little nearer to the root of 

 the caudal than to the end of the snout, and consi)icuously behind 

 the origin of the ventrals. Sides of the body with a very indistinct, 

 dark longitudinal band. 



Eastern States of North America. 



a. Adult. Kenhawa River. From Mr. Cope's Collection. 

 2. Rhiniclitliys marmoratus. 



Agassiz, Lake Superior, p. 354, pi. 2. figs. 1-2. 



D. 10. A. 8. L. lat. 70. L. transv. 12/20. 

 Barbel half as long as the eye, which is small and two-fifths of 

 the length of the snout, occupying the middle of the length of the 

 head. Snout projecting beyond the mouth. The height of the body 

 is contained five times and one-third in the total length (without cau- 

 dal), the length of the head four times and one-fourth. The origin 

 of the dorsal fin is nearly midway between the end of the snout and 



characters of the two latter species cannot be determined, descriptions 

 and figures being alike unreliable. 



4. Argjreus dulcis, Girard, I. c. p. 185 ; or in U. S. Pac. E. B. Exped. Fish. 



p. 243, pi. 54. fig. 5. — Sweet Water, Nebraska. 

 Nothing being kn^wn of the structure of the mouth of the two following fish, 

 I am not certain whether they ought to be referred to this or to some other genus. 



5. Agosia chrysogaster, Girard. Proc. Acad. Nat. Sc. Philad. 1856, p. 187, 



and U. S. cf- Mex. Bound. Ichthyol. p. 48, pi. 28. figs. 5-8.— Eio Sa Cruz, 

 Sonora. 



C\ metallica, Girard. ibid., and I. c. p. 49, pi. 29. fies. 1-4. — Rio San 



Pedro, a tributary of the Gila. 



