48 MONOGRAPH OP THE FRESH WATER III. 



than the depth. The peduncle of the tail appears more elongated than in any 

 other species. 



The head forms nearly the fourth of the total length; it being contained a little 

 more than twice in the length of the body, the caudal fin excluded. Its width is 

 equal to the length of its upper surface. The eyes are a little smaller than in G. 

 Bairdii, their form is circular, and their diameter enters five times in the length of 

 the head. The interorbito-frontal space is equal to one diameter. The anterior 

 nostril is situated nearly on the middle of the space between the end of the snout 

 and anterior rim of the eye. The posterior one is above, close to the orbit. The 

 mouth is larger than in G. Bairdii, and the palatine bones are likewise provided 

 with teeth-like asperities, forming a more elongated patch. 



The preopercular spine is very conspicuous, stout, directed obliquely upwards 

 and backwards. Under it we observe a second preopercular spine, much smaller, 

 of the size of that of the subopercular, the point of which is directed vertically 

 downwards, and below, a third, still smaller, directed obliquely forwards. The 

 gill openings are smaller, and consequently the isthmus is larger than in G. Bairdii. 



The first dorsal commences a little behind the insertion of the ventrals and is a 

 little more distant from the end of the snout than in G. Bairdii. Its shajje is very 

 different from that of the latter species ; its upper edge is very convex. There are 

 seven rays, the second and third the highest, the first is equal to the fourth, the 

 fifth, sixth, and seventh are gradually diminishing. The second dorsal, contiguous 

 to the first, commences in advance of the vent, and is composed of seventeen 

 undivided rays, the last of which is branched. The upper edge of this fin is also 

 more convex than in any other species. The origin of the anal corresponds to the 

 space between the fourth and fifth rays of the second dorsal. Its last ray is double. 

 The caudal fin is shorter than the head ; it is convex posterioi'ly as in G. Bairdii. 

 The seven middle rays are bifurcated only once. 



The insertion of the ventrals takes place immediately under the pectorals; 

 amongst the four soft xnjs the two middle ones are the longest and equal in length. 

 The two outer ones are likewise equal in size. The pectorals are shorter and 

 broader than in G. Bairdii; they scarcely reach the fourth ray of the second dorsal, 

 but leave the anal behind. Their base of insertion is oblique but nearly straight. 

 The tip of all the raj's extend beyond their membrane. 



Br. 6. D VII. — 17. A 12. C 4. I. 4. 3. I. 4. V I. 4. P 14. 



The vent is nearer the snout than the tip of the caudal. 



The lateral line runs parallel to the back; it is conspicuous until the thirteenth 

 ray of the second dorsal, where it vanishes into a series of pores so minute as not 

 to be distinguished without the aid of a lens. 



We cannot give anything positive on the color of this species, the specimens col- 

 lected by Prof. Baird having lost their general hue. The body, however, shows still 

 some faint blotches of darker appearance than the ground color; and the fins 

 appear to have been banded. 



This species inhabits the tributaries of James Eiver (Va.) . Specimens are pre- 

 served in the Museum of the Smithsonian Institution. 



