FISHES OF LAKE SUPERIOR. 253 



individual which has served for this description, the whole length 

 exceeds a little five inches. 



The general form of the body is compressed, differing still in 

 that respect from A. unicolor, which is subcylindrical, whilst the 

 concolor is cylindrical at its anterior, and compressed at its posterior 

 part. Our species is, on the contrary, in some manner ribbon-like, 

 and its length goes on diminishing regularly from the neck towards 

 the tail, where it ends in an attenuated and obtuse caudal lobe. 

 The neck is prominent, but the skull is declivous. The upper lobe 

 of the mouth, which terminates the anterior extremity, is concave, 

 the opening of the cavity which it circumscribes being turned 

 downwards. The anterior margin of the lip is concave, the lateral 

 margins describe a convex lobe to the angles of the mouth. The 

 lower lip is completely distinct from the upper, small and fixed upon 

 the anterior of the lateral margins of the upper ; it is slightly con- 

 cave about the middle of its circumference. The convex lateral 

 lobes are elliptical. The mouth, placed in the centre of the funnel 

 formed by the two lips, is proportional to the size of the fish. When 

 it is shut it seems to be cleft vertically, though in reality it is cir- 

 cular. The branched fringes which surround the mouth, are 

 especially developed on the lower lip and at the angles of the mouth ; 

 they lengthen, but are reduced in thickness, on the inner side of the 

 upper lip, under the form of an isosceles triangle, whose interior 

 is equally furnished with them. The opening of the nose is situate 

 in a circular depression betAveen the anterior extremity of the 

 skull and the inner margin of the upper lip. This depression 

 is continued upwards, and terminates about the middle of the skull. 

 The eyes are very small and placed on the sides of the head, at the 

 height of the angles of the mouth, in a slight furrow of the face. 

 The branchial openings are subcircular or convex in front, truncated 

 behind, and open in a wrinkled furrow half an inch long, in form of a 

 very elliptical curved line. The first branchial opening is at a dis- 

 tance of ~ 6 of an inch behind the angles of the mouth. The anus opens 

 in a depression at a distance of | of an inch from the extremity of the 

 caudal fin ; it is cleft longitudinally, and bordered by two thinned lips. 

 The anal fin, very low at its origin immediately behind the anus, widens 

 a little as it advances towards the caudal, with which it unites after 



