﻿,64 LAMPSILIS 



the center of the base. The shells of both male and female 

 are much thickened in front. 



Length (male) y2, height 42, diam. 32 mm. 



Length (female) 63, height 40, diam. 31 mm. 



Lower St. Lawrence drainage, to Lake Michigan; Lake of 

 the Woods. 



Type locality, Duck Island, CJttawa River, Ont. 

 Unio borealis A. F. Gkay, Tr. Ottawa Field Nat. Club, 1882, 



P- 53. Pl- 

 Lampsilis borealis Simi'Son, Syn., 1900, p. 535. 



This species combines the characters of Lampsilis luteola 

 and radiata. It often closely approaches the fomi of the for- 

 mer, but is generally more inflated. It has, however, the tex- 

 ture and roughened epidermis as well as much the same color 

 as the latter. 



Lampsilis RADIATA (Gmelin). 



Shell long obovate, subsolid, subcompressed ; posterior ridge 

 feeble or wanting; beaks rather sharp but not full or high, 

 with delicate, doubly-looped sculpture ; epidermis concentrically 

 -wrinkled, often looped, showing numerous more or less dis- 

 tinct rays on a yellowish or brownish-green ground; the left 

 valve has two pseudocordinals, the hinder under the beak, 

 .and two straight laterals ; the right valve has two pseudocar- 

 dinals, the upper smaller and compressed, and a single sub- 

 truncated lateral ; beak cavities not deep, compressed ; muscle 

 scars shallow; nacre bluish-white, sometimes dirty salmon 

 reddish or purplish, dull, somewhat thickened in front. The 

 female shell is shorter than that of the male, it is wider at the 

 posterior end. The male shell is often somewhat drawn out 

 and feebly biangulate. 



Length (male) 90, height 50, diam. 27 mm. 

 Length (female) 80, height 52, diam. 27 mm. 

 My a radiata Gmklin, Syst. Nat., 13th ed., 1792, p. 3220.— 

 W(X>D, Index Test., 2d ed., 1825, p. 12, pi. 11, fig. 2.— Han- 

 ley, Index Test., 3d ed., 1856, p. 16, pi. 11, fig. 32. 

 Unio radiata Lamarck, An. sans. Vert., VI, 1819, p. j;^. 

 Lampsilis radiata Stimpson, N. Eng. Shells, 185 1, p. 13. 



