62. LEUCOSOMtJS. 271 



hook ; the inner small and conical. Gill-rakers short, small, distant, 

 few in number, terminating in two or more irregular points. Tlie 

 attachment of the gill-membranes takes place opposite to the angle 

 of the pricoperculura. 



Western N^orth America. 



n, h. Types of the species. Columbia lliver. From the IlasLir 

 Collection. 



c. Adult. Sau Francisco. Pn ntcd by Dr. W. O. Ayrcs. 



II. Z'pper caudal lube more developed than the lower. 



8. Leucosomus insequilobus. 



Pogonichthys infequilobus, Baird ^- (urard, Proc. Ac. Kat. Sc. PJtihuI. 

 1854, p. 130 ; U. S. ^- Pac. li. li. J^xpcd. Fish. p. 245, pi. 5(J. fig^^. 1-4 

 (position of doi'sal tin incorrect). 



D. 11. A. 10. V. 10. L. lat. 59. L. transv. 10/10. Vert. 2G/15. 



The upper lobe of the caiuhd Jin is considerably longer than the 

 loiver, and the rays at the upper part of its root are unusualli/ 

 developed. The height of the body is nearly equal to the length 

 of the h-ead, which is more than one-fifth 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. The width of the 

 interorbital space, which is convex, is more than the length of the 

 snout. Snout of moderate length, subconical. Mouth subhorizontal, 

 of moderate width, the maxillary extending to the vertical from the 

 front margin of the orbit ; upper jaw overlapping the lower. Pra;- 

 orbital longer than deep, larger than the postorbital, which is wider 

 than the other suborbital bones. The origin of the dorsal fin is 

 slightly in advance of that of the ventrals, and nearly midway 

 between the end of the snout and the root of the caudal. Caudal fin 

 deeply forked. The pectoral fins terminate at a great distance from 

 the ventrals. There are six longitudinal series of scales between 

 the lateral line and ventral fin. Coloration uniform. 



Phaiyngeal teeth strongly compressed, hooked, 5 or 4 . 2 — 2 . 5. 

 Gill-rakers moderately developed, acutely pointed, claw-like. The 

 attachment of the gill-membranes to the isthmus takes place in 

 advance of the angle of the prseoperculum. 



California. 



a, b-c. Adult (11 inches long). San Francisco. Presented by Dr. 

 W. 0. Ay res. 



d. Adult male : skeleton. San Francisco. Presented by Dr. W. 0. 



Ay res. 



The skeleton does not essentially differ from that of European 

 Leucisci. The last caudal vertebrae with their apophyses are re- 

 markably strong, to offer a support for the much-developed lobes of 

 the caudal fin. 



