670 MEMOIRS OF THE CARNEGIE MUSEUM. 



EXPLANATION OF PLATE XLVIII. 



Horizontal sections of gills of Diplodon paulista (Von Ihering), Diplodon 



MOGYMiRiM Ortmann, Diplodon gratus (Lea), Diplodon deceptus 



(Simpson), Castalina nehringi Von Ihering, Fossula fossiculi- 



FERA (D'Orbigny), Monocondyl^a minuana D'Orbigny, 



AND Anodontites patagonica rubicunda (Lea); 



much enlarged ; inner gill to the left, 



outer gill to the right. 



Fig. L Diplodon paulista (Von Ihering), from creek (tributary to Rio Mogy 

 Guassu), Mogy Mirim, Sao Paulo, Brazil. Carn. Mus. Cat. No. 6L925G. Section of 

 gills of gravid female (No. 3). 



Fig. 2. Diplodon mogymirtm Ortmann, from creek (trilnitary to Rio Mogy Guassu), 

 Mogy Mirim, Sao Paulo, Brazil. Carn. Mus. Cat. No. 6L92G0. 



Fig. 2a. Section of gills of female (No. 45). 



Fig. 26 Section of gills of gravid female (No. 4). 



Fig. 3. Diplodon gratus (Lea), from Rio Uruguaj', Uruguayana, Rio Grande do 

 Sul, Brazil. Carn. Mus. Cat. No. 6L5S66. 



Fig. 3rt. Section of gills of male (No. 19). 



Fig. "ih. Section of gills of female (No. 20). 



Fig. 4. Diplodon deceptus (Simpson), from Rio Jacuhy, Cachoeira, Rio Grande 

 do Sul, Brazil. Carn. Mus. Cat. No. 61.58G8. Section of gills of half-grown female 

 (No. 6) (Shell of this specimen figured on Plate XXXIX, fig. 4). 



Fig. 5. Castalina nehringi Von Ihering, from Rio Tiete, Itapura, Sao Paulo, Brazil. 

 Carn. Mus. Cat. No. 6L5r20. Section of gills of gravid female (No. 5). 



Fig. 0. Fossula fossiculifera (D'Orbigny), from Rio Tiete, Itapura, Sao Paulo, 

 Brazil. Carn. Mus. Cat. No. 6L5840. Section of gills of female. 



Fig. 7. M onocondylwa minuana D'Orbigny, from Rio Uruguay, Uruguayana, 

 Rio Grande do Sul, Brazil. Carn. Mus. Cat. No. 61.5848. 



Fig. 7a. Section of gills of male (No. 5). 



Fig. 76. Section of gills of gravid female (No. 6). 



Fig. 8. Anodontites patagonica rubicunda (Lea), from Rio Cacequy, Cacequy, 

 Rio Grande do Sul, Brazil. Carn. Mus. Cat. No. 61.5810. Section of gills of female. 



