﻿LAMrsirjs 



157 



(July two specimens, both in the Lea collection, and one of 

 them the type, have been seen by the writer. Both are dead 

 and badly eroded. C)ne is somewhat rhomboid, the upper pos- 

 terior part being- slightly tnmcated ; the post-basal point is wide- 

 ly rounded. The other is nearly evenly rounded behind and 

 may be a female, though it has no perceptible post-basal swell- 

 ing. I cannot be certain as to the systematic position of this 

 species. Its texture and color are much like those of L. I'anu.v- 

 emensis, but the form is most like that of members of the 

 parva grou]). It is larger and much darker colored than L. 

 cylindrella, it is larger and solider than gennana, and has a 

 darker nacre. 



Lampsii.is cromweu.ii (Lea). 



Shell somewhat obovate, subsolid, subcompressed or but 

 slightly inflated, with a low, rounded posterior ridge ; beaks 

 rather high and sharp, sculptured beautifully with eight of 

 more regularly curved ridges, their curve being shorter than 

 that of the growth lines ; surface with fine growth lines, green- 

 ish-yellow, sometimes clouded with green, often having two 

 light colored rays on the posterior slope, and concentrically 

 banded with lighter color ; epidermis only moderately thick ; 

 left valve v/ith two compressed, ragged peudocardinals and 

 two curved laterals ; right valve with one irregular pseudo- 

 cardinal and sometimes a double lateral ; beak cavities shallow ; 

 posterior muscle scars faint ; nacre white or lurid, silverv, iri- 

 descent and a little thinner behind. Male shell a little rhom- 

 boid or evenly rounded behind ; female shell with a feeble, sub- 

 angular marsupial swelling, the shell behind it is truncate up 

 to the somewhat elevated posterior point. 



Length 27, height 17, diam. 12 mm. 



Western Georgia and southeastern Alabama. 



Type locality, Kiokee Creek, .Vlbany, Dougherty Co., Ga. 

 IJnio crormvellii Lea, Pr. Ac. N. Sci. Phila.. IX, 1865, p. 89; 



Jl. Ac. N. Sci. Phila., VI, 1869, p. 258, pi. xxxi, fig. 72, : Obs., 



XII, 1869, p. 18, pi. XXXI, fig. y^)- 



