﻿62 LAMrSII.lS 



Ufiio hydianns Kustkr, part. Conch. Cab. I'nio, t86i, p. 201, 



])1. i.xvii, fig:. I. 

 Unio distans Anthony, Am. Jl. Conch., T, 1865, p. 156, pi. 



XIII, fig. 2. 

 Unio mnltiradiatus SowKRnv. Conch. Icon., X\'I, 1868, pi. lxi, 



fig. 306. 

 Unio afUnis SowERHv, Conch. Icon.. X\'T, 1868, pi. i.xi, fig. 307. 



\'ar. rosacea (De Kay). 



Shell smaller and more delicate than the type, generally less 

 brightly colored, often nearly or quite rayless ; epidermis 

 brownish or pale greenish-yellow ; nacre white, bhiish or rose- 

 tinted. 



Length 60, height 2>7- diam. 20 mm. 



The St. Lawrence and Mackenzie areas. 



Type locality, Seneca Lake, N. Y. 

 Unio rosaceus De Kay, Zool. of New York, V, 1843. p. 192, 



pi. xxxix, figs. 355, 356; pi. XL, fig. 357. 

 I.ampsilis Ittteoltis van rosaceus Simpson, Syn., 1900, p. 535. 



One of the most abundant, Avidely distributed L^niones in 

 the world. It probably extends down the Mackenzie River 

 to near the Arctic Ocean and nearly to the mouth of the St. 

 Lawrence. Tt does not seem to be abundant in Kentucky or 

 the Tennessee River System. In the southwest it is mostly 

 replaced by the closely allied L. hydiana, which is often taken 

 for this species. The variety rosacea of De Kay has typically 

 a beautiful rose-colored nacre, the color in man}' cases show- 

 ing through the epidermis, but in a majority of cases this form 

 has a smoky, brownish, bronzy or lurid ash-colored epidermis 

 w^ith feeble rays. So far as I know the variety is found only 

 in the St. Lawrence and northward, but fairly typical speci- 

 mens occur throughout this region. 



Lampsii.is sui'ivRioRHNSis (Marsh). 



Shell long-obovatc, subcompressed, subsolid. without a pos- 

 terior ridge; beaks rather low; ligament prominent, brown; 

 surface covered with irregular, coarse growth lines, sometimes 

 almost sulcate, and haviuij: a limited number of faint ravs ; 



