1414 ANODONTITES 



scription. Certain specimens of Strophitus edcntulus answer 

 very well to this figure and description, excepting the some- 

 what pinched-up posterior ridge, which may not be correctly 

 drawn. I know of no South American Naiad at all like it and 

 I would not be surprised if it was a rather unusual specimen 

 of the species to which I have compared it. 



Group of Anodontites crispatus. 



Shell elliptical obovate, slightly produced at the posterior 

 base, and straight or very feebly incurved in front of it ; epi- 

 dermis fuscous or tawny, cloth-like behind, somewhat rayed 

 by more or less incised lines in front, where it is wrinkled like 

 dried paint, the wrinkles often being looped ; nacre lurid, blu- 

 ish, somewhat iridescent. 



Animal having gills of thin, semi-transparent texture, with 

 wide, vertical, light-colored ridges, the whole beautifully retic- 

 ulated under a glass, inner wider, united throughout to the 

 abdominal sac; palpi rather small, semicircular, attached along 

 their entire upper border ; mantle thin, very thick on the bor- 

 der : branchial opening with short, fleshy palpi ; anal and super- 

 anal openings united, but separated from the branchial open- 

 ing by a strong bridge. 



ANor>ONTiTEs CRISPATUS Bruguiere. 



Shell long rhomboid or long obovate, thin or scarcely sub- 

 solid, convex, inequilateral ; beaks not full or greatly elevated ; 

 posterior ridge full, rounded or faintly biangulate; anterior 

 end narrowed and rounded ; dorsal outline nearly straight ; 

 posterior end sometimes obliquely subtruncate above, some- 

 times almost evenly rounded, occasionally biangulate below ; 

 base nearly straight; in front of the posterior ridge there is 

 sometimes a broad, shallow, radial depression ; surface with 

 radial sulcations and concentric growth lines, which are broken 

 into loops at the radial grooves ; epidemiis greenish-yellow or 

 tawny ; nacre blue ; muscle scars shallow. 



Length 53, height 27.5. diam. 17 mm. 



Widely distril)uted in tropical South America. 



