﻿l66 LAMl'SILIS 



i/nio ( Laiiipsilis) rovirosai i'lLSiiuv, Xautilus, Xlll, 1900, p. 



140. 

 Laml>silis roi'irosai Simpson, vSyn., 1900, p. 568. — i'ii,siu<y, I'r. 



Ac. X. Sci. IMiila., 1903, p. 788, pi. liv, tigs. 1, lu. 



Only the type in the Philadelphia Academy of Sciences is 

 known, and this is somewhat narrowed in front, with a long 

 and rather full, rounded post-basal swelling, which does not 

 reach to the posterior end. The posterior point is blunt and 

 rounded, two-thirds of the way up from the base. It is nearest 

 to /,. purhurata but is more decidedly sulcate, the nacre is 

 much lighter colored, and the beaks are lower. The beaks of 

 the specimen seen are so badly eroded that the sculpture is de- 

 stroyed. This is probably a female, and the ix)st-basal swell- 

 ing is larger and farther from the posterior end than it is in 

 purpurata. 



Lampsii.is ruRPURATA (Lamarck). 



Shell very large, somewhat obovate, inflated, with full, high 

 beaks, having very faint, corrugated sculpture, scarcely winged 

 in front, with a low, angular wing behind ; there are two or 

 sometimes three low, radiating ridges on the posterior slope ; 

 surface nearly smooth or somewhat sulcate, covered with a 

 shining, blackish epidermis ; ligament large and long, gener- 

 ally exposed in adult shells ; left valve with two subcompressed 

 to solid, ragged pseudocardinals and two strong, remote lat- 

 erals, the hinge line rounded between the two sets of teeth ; 

 right valve with two pseudocardinals, the lower the larger, 

 and one strong, truncated lateral ; beak cavities rather deep, 

 with a row of deep scars running towards the anterior base ; 

 muscle scars large, the anterior deep and smooth, the posterior 

 scarcely impressed ; nacre rich, dark purple, somewhat irides- 

 cent behind, much thicker in front. Male shell full at the pos- 

 terior base, rounded and obtusely biangulate l)ehind above the 

 median line; the female shell has a wide, rounded, marsupial 

 swelling far behind, and is decidedly truncate posteriorly. 



Length 170, height 1 10, diani. 67 mm. 



Lenglh (female) 130, height '>o, diam. 58 mm. 



