654 MEMOIRS OF THE CARNEGIE MUSEUM. 



EXPLANATION OF PLATE XL. 



Shells of Prisodon alatus (Sowerby), Monocondyl^a obesa Ortmann, and 



Anodontites crispata BruguiJire. 



All figures natural size. 



Figs. 1-3. Prisodon alatus (Sowerby), from Rio Tapajos, Santarem, Para, Brazil. 

 Carn. Mus. Cat. No. 6L5109. 



Fig. 1. Adult specimen, lateral view. 



Fig. 2a. Half-grown specimen, lateral view. 



Fig. 26. Half-grown specimen, dorsal view. 



Fig. 2c. Half-grown specimen, inner view of left valve. 



Fig. 2d. Half-grown specimen, inner view of right valve. 



Fig. 3. Young specimen, lateral view. 



Figs. 4-6. Monocondyla;a obesa Ortmann, from Rio Tapajos, Santarem, Para, 

 Brazil. Carn. Mus. Cat. No. 6L5850. 



Fig. 4a. Half-grown specimen (No. 10), lateral view. 



Fig. 46. Half-grown specimen (No. 10), inner view of left valve. 



Fig. 4c. Half-grown specimen (No. 10), inner view of right valve. 



Fig. 5a. Young specimen (No. 5), lateral view. 



Fig. 56. Young specimen (No. 5), dorsal view. 



Fig. 6. Young specimen (No. 1), lateral view. 

 /^" Figs. 7 and 8. Anodontites crispata Bruguiere, from Rio de la Paila, Paila, U. S. 

 /of Colombia. Carn. Mus. Cat. No. 61.9274 (See also Plate XLI, figs. 2 and 3). 

 I Fig. 7a. Half-grown male (No. 8), lateral view. 



\ Fig. 76. Half-grown male (No. 8), dorsal view. 

 ^ Fig. 8. Nearly adult female (No. 10), lateral view. 



