1406 ANODONTITES 



the posterior slope. Interior pale pink within the pallial line ; 

 prismatic border faint olive-buff. There are some black zig- 

 zags along the pallial line or outlining the muscle scars. 



Colonia, Uruguay. 

 Glabaris lato-nuirginatus Lea, var. felix Pilsrry, Pr. Ac. N 



Sci. Phila., 1896, p. 563, pi. XXVI, fig. 8. 

 Glabaris patagonicns var. felix Simpson, Syn., 1900, p. 917. 



Anodontites crassus (Swainson). 



Shell irregularly obovate or somewhat pentagonal, scarcely 

 subinflated. solid, inequilateral; beaks full and high; hinge line 

 lightly curved ; dorsal slope strongly, obliquely truncate ; an- 

 terior end narrowed, rounded or subtruncate, angled above ;. 

 base line nearly straight in front, very full and subangulate 

 behind the middle ; surface with well-marked growth lines ; 

 epidermis dark grass-green ; nacre whitish with iridescent 

 tints ; muscle scars deep. 



Length 80, height 52, diam. 32 mm. 



Rio de la Plata. 

 Anodon crassus Swainson, Zool. 111., ist ser.. Ill, 1823, pi. 



CLXVII. 

 Margarita ( Anodonta) crassa Lea, Syn., 1836. p. 23; 1838, p. 



2,2. 

 Anodonta crassa Hanley, Test. Moll., 1842, p. 222. 

 Anodon crassa Catlow and Reeve, Conch. Nom., 1845, P- 66. 

 Margaron (Anodonta) crassa Lea, Svn., 1852, p. 52; 1870, 



p. 83. 

 Glabaris crassus Simpson, Syn., 1900, p. 917. 



Close to A. patagonicus. but I have never seen a specimen 

 of that species quite so elongated or so pentagonal as the fig- 

 ure represents Swainson's shell to be. His shell is said to be 

 deep grass-green, while patagonicus is always more or less 

 brown, it has its greatest diameter well forward while that of 

 patagonicus is at the middle. Swainson gives no measure- 

 ments and T have given those of his figures. 



It is claimed in the Testacea Fluviatilia that this is the same 

 as the Anodon gigantcus of Spix. but this is certainly an error. 



