1428 ANODONTITES 



This may be a true Anodonta related to A. cxUior. I have 

 never seen it and the description is rather brief, while the fig- 

 ures give no characters by which I can decide. It is very 

 slightly obovate, thin, with a rough yellow and green epider- 

 mis. 



Group of Anodontitcs trapesialis. 



Shell large, inflated, elliptical, narrower in front, with full, 

 rather prominent beaks, a slight wing on the post-dorsal part, 

 and sometimes a small one in front of the beaks ; gaping de- 

 cidedly in front and slightly behind ; epidermis smooth, gener- 

 ally uniform olive-green ; hinge line straight or slightly sin- 

 uous ; escutcheon large and conspicuous ; nacre bluish-silvery, 

 sometimes marked with parallel, wavy dark lines. 



Animal with the marsupium filling the inner branchiae ; gills 

 large, inner the larger ; palpi very large, reniform ; mantle thin, 

 with a wide, thickened edge : branchial opening small, plicate, 

 but not crenulate or papillose ; anal opening large, smooth, 

 separated from the branchial by a strong bridge. 



Anodontites Trafe.sialis (Lamarck). 



Shell large, subinflated, rather thin, irregularly obovate or 

 subtrapezoid. inequilateral : beaks large, full and elevated ; 

 hinge line nearly straight, usually slightly arched ; anterior end 

 narrowed, rounded, sirbangulate above, often slightly cut 

 away below; base line rounded, frequently fuller just behind 

 the middle ; posterior end obliquely truncate above, rounded 

 or drawn out to a blunt point at or below the median line ; sur- 

 face with light growth lines ; epidermis yellowish-green, green- 

 ish-tawny to ashy-green, darker and often broadly, faintly 

 rayed on the dorsal slope, sometimes feebly rayed on the disk ; 

 dull or subshining; nacre bluish to- flesh-color, generally iri- 

 descent behind : pallial line often having a faint, posterior 

 sinus ; muscle scars shallow. 



Length 145, height 82, diam. ^t^ mm. 



Length 120, height ^2, diam. 46 mm. 



Tropical South .Vmerica from Brazil and Peru southward. 

 Anodonta trapesialis Lamarck, An. sans. A-'ert., VL 1819, p. 



87. 



Fridiiia trapesialis d'ORmr.Nv. Guer. Mag., 1835, p. 43. 



