﻿472 rnc.iAs 



Margaritana elliptica Li:a, Pr. Ac. X. Sci. IMiila., IIJ, 1859, p. 



113; Jl. Ac. N. Sci. Phila., \ , 1862, p. 106, pi. xviii, fig. 254; 



Obs., \'III, 1862. p. 110, ])1. XVIII, fig. 254. 

 Margaron (Moriiaritana ) elliptica 1j:.\, Syn., 1870, p. 68. 

 Mariiaritona ( .Masmodonto) elliptica Ci.essin, Conch. Cab.- 



Ano., 1876, p. 270, pi. Lxxxi, figs. 5, 6, 

 Anodonta shoii-alterii Lea, Pr. Ac. N. Sci. Phila., IV, i860, p.- 



307; Jl. Ac. N. Sci. Phila., 1862, p. 215, pi. xxxiu, fig. 284-; 



Obs., IX. 1863. p. 37, pi. ^cxxiii, fig. 284. — ClesSin, Conch. 



Cab. .\no., 1874. ]). 156. pi. 1,1, figs. 5, 6. 

 Anodon sliowalterii Sowerhy, Conch. Icon.. XMI. 1870. pb 



XX vn, fig. 104. 

 Margaron (Anodonta ) shoivalterii Lka, Syn., 1870, p. 79. 

 Strophitiis cdrntiiliis (part), Simpsox. Syn., 1900. p. 617. 



I placed this species in Strophitiis with some doubt when 1 

 wrote the vSvnopsis. Since writing that I have seen other 

 specimens, which show something of the beak sculj^ture, and 

 J am rather inclined to believe that it is closely allied to A. 

 ferussacianus. The teeth are better developed than in that 

 species, but the nearly straight hinge line and the beak sculp- 

 ture would seem to indicate that it is an Anodontoides. C)n 

 comparing again Lea's Anodonta shoivaltcrii with his Mar- 

 garitana ellioitii I am satisfied that the two are identical, the 

 former being merely a little more solid and having a slightly 

 heavier hinge. I had overlooked the fact that Lea in describ- 

 ing the soft parts of the former states that the "Piranchial 

 uterus is filled with embryonic shells the whole length of the 

 outer leaves" as in Anodonta fernssaciana and not as in A. 

 edentnla. The beak sculpture of this form is rather delicate. 



Genus PEG! AS Simpson. 1900. 



Pegias Simpson, Syn., 1900, p. 660. 



Shell small, thickened in front, with a sharp posterior ridge, 

 in front of which is a wide radial depression, ending in a basal 

 sinus ; above this ridge is another, making the shell decidedly 

 biangulate and truncate behind ; beak sculpture consisting of 



