﻿400 anodonta 



Anuuo-N'Ta suBOKiucuLATA Say. 



Shell large, irregularly short ovate, thin but strong, gaping 

 in front and behind, subintlated, with low beaks, which are 

 compressed in young shells but fuller in old ones, their sculp- 

 ture a few irregular, feeble undulations, each bar usually hav- 

 ing small, sharp tubercles, these tubercles form two imperfect- 

 ly radiating rows ; dorsal line somewhat curved, ending in 

 front and behind in a small wing or angle ; dorsal slope trun- 

 cated, its outline incurved just above the low posterior ridge; 

 the rounded posterior ])oint about at the median line ; base line 

 rounded ; anterior end rounded, sometimes cut away a little 

 below ; surface smooth and shining in young shells, pale, yel- 

 low-green, beautifully and delicately rayed, with three broad 

 rays behind ; in old shells the outer growth is concentrically 

 sculptured and the epidermis is smoky or ashy, often banded 

 and nearly or quite rayless ; nacre silvery and iridescent, tinted 

 bluish or purplish. 



Length 153, height 120, diam. 55 mm. 



Length 170, height 120, diam. 65 mm. 



Nebraska ; Iowa ; Illinois ; south to Louisiana. 



Type locality. Ponds near the Wabash River. 

 Anodonta suhorbiciilata Sav, Xew Harm. Diss., (newspajier 



form). January 29, 1831 ; .Am. Conch.. T, No. II, 1831, pi. 



XI. — Chenu, Bib. Conch., ist ser.. III. 1845, p. 18, pi. iii, 



figs. I, ifl. — Clessi.v, Conch. Cab. Ano.. 1874. p. 160, pi. 



Lii, figs. I. 2. — Simpson, Syn., 1900. p. 636. 

 Mari!;arita f.lnodonta) sitborhiciilata Lica, Syn.. 1836. p. ^.2: 



1838. p. 31. 

 Anodon suhorbiculata Cati.ow and Rekvk, Conch. Norn., 1845. 



p. 68 

 .\far;^aron f Anodonta) suhorbiculata Lka, Syn.. 1852. p. 51; 



t870. p. 81. 

 Anodon suborbicuhitus SownRr.v, Conch. Icon.. XVII, 1867, 



pi. V, fig. II. 



Probably the finest Anodonta in the world. When young it 

 is smooth and shinino- and marked throughout with delicate 



