308 LAKE SUPERIOR. 



truncated, terminated by a kind of hog's snout, which perceptibly 

 exceeds the lower jaw, without, however, sloping over it. The mouth, 

 very slightly protractile, moderately opened, resembles an oblique arc 

 of a circle, and opens at the end of the snout. The opercular 

 apparatus and the cheeks are covered with scales, 



Besides the species here described, Etheostoma Caprodes Raf., 

 and Pileoma semifasciatum Dekay must rank in this genus. 



PlLEOMA ZEBRA, AgaSS. 



This species is very near the Etheostoma Caprodes Raf. (Pile- 

 oma Caprodes Ag.) from which it diifers only in a few peculiari- 

 ties of the structure of the opercular apparatus, in the direction of 

 the lateral line, and in the proportional size of the eyes. Pileoma 

 Caprodes attains larger dimensions than our P. zebra, the largest 

 specimens which we have had at our disposal, measuring only about 

 seven inches. Our species is figured Plate 4, figure 4, under the 

 name of Etheostoma zebra. 



The general form of the species under consideration is elegant 

 and regular. The upper outline of the body describes a slight curve, 

 rising highest at the middle of the first dorsal; it curves more 

 abruptly on the head than on the side of the tail, where it becomes 

 a little concave on the space contained between the hinder margin 

 of the second dorsal and the insertion of the caudal. The abdo- 

 men is less convex than the back ; from the insertion of the anal, the 

 outline rises and becomes slightly convex beyond this fin. The great- 

 est height perpendicularly above the first dorsal is three-eighths of an 

 inch. The greatest thickness, which corresponds to the same region, 

 amounts to about two-thirds of the height. These proportions of the 

 height and breadth are maintained uniformly along the whole body, 

 from which a regularly compressed form, from the head to the tail, 

 results. The head is conical, more pointed than in the other species 

 of the genus, and forms the fourth part of the length of the body. 

 The surface of the head is smooth. The eyes are large and subcir- 

 cular, one-seventh of an inch in diameter, and situated at the upper 

 margin ; the distance between them exceeds their diameter. The 

 openings of the nostrils are two on each side, placed one before the 



