652 MEMOIRS OF THE CARNEGIE MUSEUM. 



EXPLANATION OF PLATE XXXIX. 



Shells of Diplodon deceptus (Simpson), Diplodon (Cyclomya) paranensis (Lea), 



AND Castalia undosa Von Martens. 



All figures natural size. 



Figs. 1-5. Diplodon deceptus (Simpson), from Rio Jacuhy, Cachoeira, Rio Grande 

 do Sul, Brazil. Carn. Mus. Cat. No. 61.5868. 



Fig. la. Adult male (No. 10), lateral view. 



Fig. lb. Adult male (No. 10), dorsal view. 



Fig. Ic. Adult male (No. 10), inner view of left valve. 



Fig. Id. Adult male (No. 10), inner view of right valve. 



Fig. 2. Adult male (No. 11), lateral view. 



Fig. 3. Half-grown male (No. 4), lateral view. 



Fig. 4. Half-grown female (No. 6), lateral view. 



Fig. 5a. Young specimen (sex ?) (No. 2), lateral view. 



Fig. 5b. Young specimen (sex ?) (No. 2), dorsal view. 



Figs. 6 and 7. Diplodon {Cyclomya) paranensis (Lea). 



Fig. 6. Nearly adult female (No. a), lateral view, from Rio de la Plata, San Isidro, 

 Argentina. Carn. Mus. Cat. No. 61.9265. 



Fig. 7. Young specimen, lateral view, from Rio Paraguay, Corumba, Matto 

 Grosso, Brazil. Carn. Mus. Cat. No. 61.2031. 



Fig. 8. Castalia undosa Von Martens, from Rio Tiete, Itapura, Sao Paulo, Brazil. 

 Carn. Mus. Cat. No. 61.5116. 



Fig. 8a. Half-grown specimen, lateral view. 



Fig. 86. Half-grown specimen, dorsal view. 



Fig. 8c. Half-grown specimen, inner view of left valve. 



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



