FISHES OF LAKE SUPERIOR. 349 



in this latter, the back is arched from the occiput, but the curve is 

 more uniform, the nape of the neck being less prominent, and the 

 belly also less swollen. The body is thicker and stouter than in the 

 O. sapidissimus, compressed, fusiform ; the greatest height, which is 

 measured vertically at the anterior margin of the dorsal, is contained 

 four times in the length, the caudal included. The lines of the back 

 and belly come near each other on the tail, without abrupt transition ; 

 they continue on the head, without rising much on the lower face, 

 and without lowering much on the upper face, though the skull is 

 depressed and slightly sloping. The head, which is thicker and 

 stouter, forms one-fifth of the whole length, including the caudal. 

 It is less pointed than in the preceding species, and the rostrum 

 more obtuse, less exceeding the lower jaw. The mouth is somewhat 

 larger, but constructed in the same manner ; that is to say, the 

 ascending branches of the lower maxillary shut themselves up beneath 

 the suborbital bones, and there is a cutaneous appendix at the anterior 

 margin, and a kind of lips, which form the angles of the mouth by 

 uniting with the labials. These latter are broader than long, passing 

 beyond the anterior margin of the orbit. Their terminal extremity 

 has likewise the long and pear-like shield, which we have indicated in 

 O. sapidissimus. The lower jaw, again, is surrounded with a folded 

 lip, imitating a border of fringes. We have remarked no trace 

 of teeth on the intermaxillaries, and without deciding upon their 

 absence, they were at least obliterated so as to render them doubtful. 

 The tongue is broad and shows no trace of asperities at its surface. 

 The eyes are large, almost circular, and placed in the same relative 

 position. The nostrils are nearer to the orbits than to the extremity 

 of the rostrum. The suborbitaries present no remarkable difference, 

 unless it be, perhaps, that they encroach less on the cheeks. 



In the opercular apparatus, we remark that the operculmn is 

 rather quadrangular, and the suboperculurn more contracted at its 

 posterior extremity, which renders its lower margin more oblique. 

 The iuteroperculum is somewhat more uncovered. 



The fissure of the gills is the same, but the branchiostegal appara- 

 tus is more developed and the rays more bent ; their actual number 

 is eight. 



The scales are somewhat larger than in the preceding species, and 



