﻿152 I.AMPSILIS 



Lenirth 32, lieijj^lit 17, diam. (of male) 13 and (of female) 

 21 mm. 



Mississippi River drainage generally ; southwest to central 

 Texas ; western New York ; southern Canada ; and Michigan. 



Type locality. Fox River. 

 Unio parinis Barnks. Am. Jl. Sci., VI, 1823, pi. xiii, fig. 18 



(outline). — I'milit'Im, Abhild.. I. 1845, P- i'-'< P^- ^ ^S- 4- — 



KusTiiR, Conch. Cah. Unio, 1852, p. 33, pi. v, fig. 5. 

 Margarita (Unio) pai-i'us I.ka, Syn., 1836, p. 28; 1838, p. 21. 

 Margaron (Unio) pari'us Lua, Syn., 1852, p. 31 ; 1870, p. 49. 

 Lampsills parinis Kaker, Moll. Chi., Pt. I, 1898, ]). 109, pi. xiii, 



fig. 3. — SiMTSON. Syn., 1900, p. 564. 

 Mya parva Eaton, Zool. Text-Book, 1826, p. 222. 

 Bitryriia fCarunciilina) parva Ortmann, Ann. Car. Mus., 



VIII, 19 1 2, p. 338. 



This species has often been confounded with L. texasensis, 

 to which it is not very closely allied. Even Dr. Lea placed 

 several specimens of the latter with his pari'o. It differs from 

 all other members of the group in having the female shel*. 

 greatly inflated, and in having the shells of both sexes almost 

 evenly rounded behind. Generally it is one of the smallest of 

 the Uniones, but it sometimes attains a length of two inches. 



Lampsujs halfjana (Lea). 



Shell long elliptical or obovate, subinflated, scarcely subsolid ; 

 beaks somewhat full and raised above the dorsal outline, sculp- 

 tured with seven or eight strong, singly looped ridges, which 

 are wel curved up l>ehind : sometimes the beak sculpture is 

 slightly doubly looped ; surface with numerous low, irregular, 

 concentric ridges, rayless or nearly so, and covered with an 

 olive-green or brown epidermis ; left valve with two compress- 

 ed, slightly recur\'ed pseudocardinals, and two curved laterals ; 

 right valve with one compressed pseudocardinal and one lat- 

 eral ; beak cavities and adductor scars shallow ; nacre silvery, 

 bluish-white, iridescent, and a little thinner behind. Male shell 

 a little full and subangular in the post-basal region with a 

 rounded point behind midway up from the base ; female shell 

 shorter, somewhat obovate, with a full, rounded marsupial 



