286 LAKE SUPERIOR. 



say, the intermaxillaries form alone the upper margin of the mouth, 

 and the maxillaries stand behind as a second arch, but the vomer and 

 palate are entirely destitute of teeth. 



This fish, of which I shall publish a full anatomy, should be consid- 

 ered as the type of a distinct family, under the name of Peroopsides. 



PERCOPSIS GUTTATUS, Agass. 



PI. L, fig. 1 and 2. 



This is a fish of small size and slender form, though the back is 

 very much elevated. Its greatest elevation corresponds to the an- 

 terior part of the dorsal fin, that is to say, a little nearer the end of 

 the snout than the insertion of the caudal. The tail is proportionally 

 elongated, a little compressed between the adipose fin and the basis 

 of the caudal. The sides are compressed, and diminish gradually in 

 thickness from the front backwards. The ventral line is less promi- 

 nent than that of the back ; it rises more backwards of the anal, to 

 concur in the contraction of the tail. The profile of the head, which 

 is small and compressed like the sides, is regularly conical; the 

 length of the head is contained three times in that of the body, set- 

 ting aside the lobes of the caudal. 



The eyes are large and circular, situated near the upper margin 

 of the face ; if a vertical line passed through their centre, it would 

 divide the head into equal parts. The space which separates the 

 anterior margin of the orbits from the end of the snout, is about half 

 an inch. The nostrils open outwards by a double opening, and are 

 very near the eyes. One of these openings has the form of a cres- 

 cent, whose convexity is turned towards the eye ; the other is small, 

 subcircular and situated in the concave space of the preceding. 

 (Fig. 2.) The mouth is small, and appears scarcely larger when 

 opened ; the upper jaw extends beyond the lower, and is formed solely 

 by the intermaxillaries, upon which we remark a narrow band of 

 small, excessively fine teeth, arranged like the teeth of a card. The 

 palate is entirely smooth. On the contrary the pharyngeans are 

 covered with similar teeth still more slender, as also the oesophagean 



