FISHES OF LAKE SUPERIOR. 351 



opening is quadrangular as in the adult. The intermaxillaries have 

 a row of very fine teeth ; there are teeth even on the margin of the 

 lower jaw, but more difficult to perceive even with the magnifying 

 glass. The surface of the tongue is prickled with small, very acute 

 asperities, like the teeth of the intermaxillaries. The eyes are very 

 large ; the distance which separates them from the end of the snout 

 does not equal their diameter ; the nostrils occupy the middle of this 

 space. 



The scales, which are stronger and larger, as we have already 

 seen, easily fall off; we may already signalize in them the same pe- 

 culiarities which we have seen in the adult. The lateral line is 

 straight and approaching slightly more to the back than to the belly. 



When ten inches in length, this fish acquires an increasing height ; 

 the height, taken before the dorsal, is contained exactly four times in 

 the length, the caudal included, and the head has almost the propor- 

 tions of the adult. The body is very compressed and flattened ; its 

 thickness is contained three times and a half in the height. The snout 

 is somewhat more prominent, as in the preceding age, though renicViv 

 ing more truncated and shorter, as in the O. sapidissimus. The 

 scales grow gradually firmer ; those of the upper half of the body 

 somewhat shorter than those of the lower half. The fins themselves 

 grow more prominent. The species is common along the northern 

 shore of Lake Superior, where it is found with C. sapidissimus. I 

 have collected a large number of specimens at the Pic. 



COREGONUS QUADRILATERALIS, Richards. 



Among the Coregoni collected at Lake Superior there is one very 

 similar to C. quadrilateralis of Dr. Richardson, though I have yet 

 doubts as to its identity. The question can only be decided by 

 comparison of specimens from the localities where the author of the 

 Fauna Boreali-Americana collected his. I have already noticed 

 slight differences in the scales, in the structure of the fins, in the 

 opercular and branchiostegal apparatus, and in the proportions of the 

 body ; differences which depend, perhaps, upon the age and size, and 

 which I have not been able to verify in all my specimens, they being 

 below the dimensions which Richardson assigns to his species. I 



