136 [August, 



dorsal fin. The head is subcorneal and contained exactly four times in the 

 length, the caudal fin excluded. The mouth is comparatively large, although 

 the posterior extremity of the intermaxillary does not quite extend to the anterior 

 rim of the eye : the snout being prolonged, and the cleft of the mouth nearly 

 horizontal. The eye is subcircular and its diameter contained five times and a 

 half in the length of side of head. The anterior margin of the dorsal is nearer 

 the end of snout than to the tip of central rays of caudal. The caudal itself is 

 forked and participates of the slender appearance of the body. The origin of 

 anal is situated behind the base of the dorsal, but at the same time in advance 

 of the tip of the rays of the latter. The insertion of ventrals is situated in advance 

 of the anterior margin of dorsal ; their tip reaching the anus. 



D II. 9. A II. 9. C 8. 1. 9. 8. 1. 9. V I. 9. P 16. 



The scales are semicircular and of medium size. The lateral line forms an open 

 curve along the sides, the convexity of which is downwards. 



Upper regions of body and head brown ; sides yellowish ; abdomen whitish. 



From Rio San Joaquin, Cal. 



Genus POGOXICHTHYS, Girard. 



Shape of mouth as in Gila; angle of mouth provided with a small filiform 

 barbel. Body fusiform and compressed. Caudal forked. Insertion of ventrals 

 behind anterior margin of dorsal. Scales large and uniform. Lateral line below 

 middle of flanks. 



This genus represents in the western waters of North America that of Gobio, 

 to which it is intimately related. 



18. Pogonichthys injEquilobus, B. and G General form very regular, sub- 

 fusiform and compressed. Total length of specimen described, about ten inches, 

 of which the head forms a little less than the sixth part. The eye is subcircular ; 

 its diameter comprised about five times in the length of side of head. The mouth 

 is of medium size; its cleft does not extend to a vertical line which would pass 

 in advance of the orbit. A barbel, about an eighth of an inch, may be observed 

 at the angle of the mouth. The origin of dorsal fin is equidistant between the 

 extremity of the snout and the first rudimentary rays of the caudal. The caudal 

 is long and deeply-forked ; its upper lobe projecting beyond the lower, although 

 the structure of that fin is perfectly homorcercal. The anal is inserted behind 

 the dorsal. The insertion of the ventrals is situated a little behind the origin of 

 the dorsal, and consequently a little nearer the rudimentary rays of caudal than 

 to extremity of snout. The pectorals are moderate. 



D II. 9. A II. 9. C 8. 1. 9. 8. 1. 7. V I. 9. P 17. 



The scales are large ; fifty-six of these may be counted in the lateral line, 

 which, upon the abdomen, approximates more to the ventral than the dorsal 

 outline. The upper legions of head and body are greyish brown ; the sides and 

 abdompn yellowish. The fins partake of the color of the region of the body to 

 which they belong. 



From the San Joaquin river, Cal. 



19. Pogoni 'hthys symmetricus, B. and G. The specimens before us being 

 in a rather poor state of preservation, a description of the species can hardly be 

 drawn with accuracy. The size of the largest is about four inches and a half in 

 total length ; the profile of body is subfusiform, very compressed, and gracefully 

 elongated. The head constitutes the fifth of the length. The eye is large and 

 its diameter contained less than four times in the length of side of head. The 

 lobes of the caudal fin are symmetrical. The anterior margin of dorsal is equidis- 

 tant between the end of snout and the extremity of central rays of the caudal. 

 The lateral line forms a gentle curve, convex downwards, upon the middle of 

 the abdomen, and nearer the insertion of ventrals than base of dorsal. The in- 

 sertion of ventrals is situated in advance of the anterior margin of dorsal, a char- 

 acter which will at once enable us to distinguish this species from P. 

 inasquilobus . 



From Fort Miller, San Joaquin Valley, Cal. 



