﻿142 I.AMI'SII.IS 



should grou]) licrc. It differs from amya^daluDi in its color, 

 in havinc^ its j^reatest diamieter well towards the posterior end, 

 in having- a dull colored nacre, and in beinj::;' much iniore nearly 

 equilateral. 



The name conca^'us applied by Lea was. I believe, used by 

 Zelebor for what seems to be U. tumidus. 



I.AMi'Sii.is VESicuLARis (Lea). 



Shell small, subinflated, scarcely subsolid. elliptical or obo- 

 vate, with a very low posterior ridge ; beaks apparently low, 

 but so eroded in the specimens seen that nothing of their char- 

 acter could be made out ; surface having irregular growth lines, 

 brownish or dirty yellowish-green, with only the faintest indi- 

 cations of rays, somewhat shining, darker behind ; left valve 

 with two low pseudocardinals, the front one rather elongated, 

 the hinder triangular, and two straight laterals ; right valve 

 with one pseudocardinal, a vestige of one above it, and an- 

 other behind it. with one lateral ; beak cavities very shallow, 

 with two or three small dorsal pits ; muscle scars small, well 

 impressed, the anterior ones separate ; nacre whitish-silvery, 

 brilliantly iridescent behind. The female shell has a rounded 

 marsupial swelling. 



Length 32. height 19. diam. 12 mm. 



Type locality. Lake Okeechobee, Sumpter County. Florida. 

 Also, Flint River, Georgia. 

 Unio vesicularis Lea, Pr. Ac. N. Sci. Phila., H, 1872, p. 156; 



Jl. Ac. N. Sci. Phila., VIII, 1874, p. 37, pi. xii, f^g. 34. ; Obs., 



XIIL 1874, p. 41, pi. XII, fig. 34. — Simpson, Pr. U. S. N 



Mus., XV, 1892, p. 425, pi. Lxvii, fig. 4. 

 LampsiHs z'esicularis Simpson, Syn., 1900, p. 562. 



Two shells bearing this name are in the Lea collection, one 

 a pair of matched valves, which I think are a variety of lepidns, 

 and these are from female shells. The other, the figured type, 

 is smoother, more shining, much more silvery within, is rather 

 elongated, lightly obovate, nearly evenly rounded at both ends 

 and is probably a male shell. It seems nearest to L. singley- 

 ano. Tt is very close to forms of omyi^dahtm and T have seen 



