ANODONTITES 1 433 



on the median line ; hinge line lightly arched behind, nearly 

 straight in front ; anterior end narrow, rounded, angled above ; 

 base line curved, a little fuller behind the middle; dorsal slope 

 obliquely subtruncate ; surface with irregular, concentric sculp- 

 ture; epidermis greenish-brown, subshining; nacre flesh-color, 

 often with letter-like or zigzag, dark markings ; muscle scars 

 impressed ; pallial line remote from the border. The valves 

 gape widely along the anterior part and slightly behind. 



Length 138, height 80, diam. 60 mm. 



Rio de la Plata. 

 Glaharis simpsonianus Pilsbry, Pr. Ac. N. Sci. Phila., 1896, 



p. 564, pi. XXVII. fig. 13. — Simpson, Syn., igoo, p. 925. 



A remarkably solid, inflated species, which has a nearly 

 evenly elliptical outline. The epidermis is more brownish than 

 in most specimens of A. trapcsialis. 



Anodontitks sinuosus (Lamarck). 



Shell trapezoid, inflated, thin, inequilateral, hinge line de- 

 cidedly sinuous, being arched behind the beaks and incurved 

 in front of them ; anterior end narrowed, rounded below, 

 sharply angled above^, base straight to considerably incurved 

 medially ; posterior end wide, obliquely subtruncate above, 

 rounded below ; beaks full and elevated ; surface having irregu- 

 lar growth lines ; epidermis olive-green, sometimes slightly 

 rayed ; nacre whitish or bluish-white, iridescent. 



Length 85, height 53 mm. 



Length 98, height 56, diam. 39 mm. 



Brazil. 

 Anodonta sinuosa LaiMarck, An. sans Vert., VL 1819, p. 87. — 



Deshayks, Enc. Meth., II, 1827, p. 147, pi. cciii, fig. 2. — 



Hanley. Biv. Shells, 1843, P- 224, pi. xxiv, fig. 16. 

 Margarita f Anodonta) sinuosa Lea, Syn., 1836, p. 54; 1838, 



P- 32. 

 Anodon sinnosa Cati.ow and Reeve, Conch. Nom., 1845, P- ^8. 

 Mar^aron f Anodonta) sinuosa Lea, Syn., 1852, p. 53 ; 1870, 



p. "83. 

 Anodon sinuosus Sowei^by, Conch. Icon., XVII, 1867, pi. viii. 



%• 15- 



