Synopsis Fresh-Water Moeeusca 



21 



Genus RHODACiAIEA Walker, 191 7. 

 Shell and animal as in the subfamily. 



Key to the sections of Rhodacinea. 



Shell elevated. Radula having the base of the central tooth ex- 

 panded and not overlapped by the mesocone of the first 

 lateral Rhodacinea s. s. 



Shell depressed. Base of central tooth of radula not expanded, 



overlapped by the mesocone of the first lateral. . . .Rhodocephala. 



Section RHODAC^IEA s. s. 



Shell elevated. Radula with a unicuspid central, 

 which has the base triangularly expanded ; laterals with 

 the cusp of the mesocone extending but little beyond the 

 base and not overlapping the base of the central tooth. 

 Type: Ancylus filosiis Con., fig. 63. Radula, fig. 64. 



Fig- 63 



Fig. 64 



Section RHODOCEPHALA Walker, 1917. 



Shell depressed. Radula with a faintly bicuspid 

 central, which has the sides of the base straight and 

 not expanded; laterals with the cusp of the mesocone 

 extending far beyond the base and overlapping the 

 base of the central tooth. 



Fig. 65 



Fig. 66 

 Type: Rhodacinea rhodacuie Walk., fig. 65. Radula, fig. 66. 



