GREAT LAKES COREGONIDS 



417 



Leucichthys nigripinnis has been described from Lake Michigan and also has 

 been recorded from Lakes Superior, Huron, Ontario, and Nipigon. In all the lakes it 

 is distinguished by the large size it attains, its deep body (which is ovate in side view) , 

 and by its relatively long paired fins. In all but Superior and Ontario the species 

 bas conspicuously pigmented fins, and in all but Nipigon it inhabits by preference 

 depths of 60 fathoms and more. The Huron form differs from the type form chiefly 

 in having a larger head and eye, possibly fewer lateral-line scales, and slightly longer 

 paired fins. The Superior form has fewer gill rakers, a longer head and snout, a smaller 

 eye, less body depth, a shorter mandible, and paler fins than the typical form. In 

 addition, it spawns in September as compared with December and January in the 

 other Great Lakes. In Nipigon the form is distinguished chiefly by having slightly 

 more gill rakers than the type, fewer lateral-line scales and scale rows, a larger head 

 and eye, and longer pectorals. The fins are somewhat darker and the body paler. 

 It frequents much shallower water and probably spawns about the same time as the 

 Michigan form. The Ontario form probably was but little different from the typical 

 race except that probably it was less pigmented. The race in Lake Nipigon has been 

 designated regalis in this paper. The Lake Superior and Lake Ontario forms have 

 been described as distinct species and called cyanopterus and prognathus, respectively. 

 They are here regarded as subspecies. 



Type 



The type is no longer extant. The name is based on a specimen sent by Hoy to 

 Gill, who named but did not describe it. The name is fixed by a cursory account 

 published by Hoy in 1872. 



Leucichthys nigripinnis nigripinnis of Lake Michigan 



The blackfin is one of the largest of the deep-water Leucichthys. It not infre- 

 quently reaches a length of 35 centimeters (13% inches), with a weight of a little 

 more than pounds, and nets of 3^ to 4 inch mesh were used to take it when it 

 supported a fishery. The body is, in general, similar in shape to that of johannx; as a 

 rule, however, it is less elongate and slightly deeper. The depth is usually equal to 

 25 to 29 per cent of the total length. The width is about 47 to 52 per cent of the 

 depth. At the occiput the dorsal profile rises rapidly to half the distance that sepa- 

 rates the occiput from the dorsal. The remaining half of the contour line continues 

 to the dorsal with only a slight upward trend. From the dorsal the contour continues 

 ventrad and caudad in nearly a straight line to the adipose. The ventral profile, 

 from the tip of the mandible to the ventral fins, runs like the opposite dorsal line. 

 For the anterior half of this distance the line curves strongly downward and back 

 ward, while the remaining half runs nearly parallel to the dorsal line and the linea 

 lateralis. The portion of the body from the dorsal and ventrals to the head appears, 

 therefore, to be of nearly uniform depth. As the depth increases the more vertical 

 become the lines proceeding immediately from the occiput and the isthmus. From 

 the ventrals the ventral contour line continues caudad and dorsad in a moderate 

 curve. The head is moderate, broadly triangular as viewed from the side, and is 

 ■contained (3.8) 4.1-4.4 (4.7) 78 times in the total length of the fish. The premaxil- 



78 These values and those given subsequently, unless indicated otherwise, are based on an examination of 52 specimens, which 

 range in length between 220 and 360 millimeters. 



