'2-iS cviKiNiD.i:. 



slightly compressed, its depth beiug one-fifth of the total length 

 (without caudal) ; the length of the head is one-fourth of it. Males 

 with two brown longitudinal bands — one from the snout, through 

 the eye, below the lateral line to the caudal, the other from above 

 the gill-opening to the caudal. The remainder of the side and belly 

 silvery (the latter reddish in the spawning-season). Females with 

 the bands indistinct. 



Pharyngeal teeth 4 or 5 — 5. 



Ohio ; Michigan. 



This diagnosis is taken from a fine example in the Liverpool 

 Museum, 2^ inches long. 



Mr. Cope distinguishes another species under the name of Chro~ 

 somus COS, Proc. Ac. Nat. Sc. Philad. 1861, p. 523; or Trans. Am. 

 Phil. Soc. xiii. p. 391. It is said to be distinguished by a "mouth 

 not reaching line of orbit, by the dark lines united on caudal pe- 

 duncle ; no lateral line." Susquehannah lliver. 



3. TIw dorsal Jin commences hcliind the root of the ventrak. Hudimcntal 

 c((tid(d rays invch dcvcloijcd. Pharynyecd teeth in a single series 

 (Lavinia). 



57. Leuciscus exilicauda. 



Lavinia exilicauda^ Baird S,- Girard, Proc. Ac. Nat. Sc. Philad. 1854, 

 p. 1.37, and 185G, p. 184 ; U. S. Pac. P. P. Ea>ped. Fish. p. 241, pi. 54. 

 figs. 1-4. 



compressa, Ayres, Proc. C'dif. Acad. Nat. Sc. 1855, p. 21. 



D. 4-10. A. 4-11. V. 11. L. lat. 60-G5. L. transv. 13/11. 



The simple caudal rays are unusually strong. The height of the 

 body is contained four times in the total length (without caudal), 

 the length of the head four times and two-thirds. Head compressed. 

 Snout of moderate extent, longer than the eye, the diameter of which 

 is one-fifth of the length of the head, and at least one-half of the 

 width of the interorbital space, which is convex. Mouth anterior, 

 oblique, with the jaws nearly even. The maxillary does not reach 

 the vertical from the front margm of the orbit. Prosorbital a little 

 smaller than the postorbital, which is not twice as wide as the pre- 

 ceding suborbital. Origin of the dorsal fin considerably nearer to the 

 root of tho tail than to the end of the snout, behind the base of the 

 ventrals. Anal fin ncarlj' as long as high, caudal broad, deeply 

 forked. The Icjigth of the pectoral equals that of the ventral, and 

 is throe-fifths of the distance of its root from that of the ventral. 

 Coloration uniform. 



Gill-rakers slender, lanceolate ; pharyngeal teeth 5 — 5, com- 

 pressed, not denticulated, claw-shaped. 



California. 



a-h, c. Ten and eleven inches long. San Francisco. Presented by 

 Dr. W. 0. Ayres. 



The description of Lavinia harenqus, Girard, Proc. Ac. Nat. Sc. 

 Philad. 1850, p. 184, or U. S. Pac. E. R. Exped. Fish. p. 242, from 

 Monterey Plains, is of a very dubious character; moreover the 



