550 



^ 



f:^ 



Opercles subspiral: inhabit rapid Peristome continuous; fool 

 streams: oviparous. large, oblong. 



Peristome not entire, foot Inhabit quietwaters: oper- 



oval. cles mostly concentric. 



^ 



bJO 



.g ^ 



.2 =^ 





b -^ 



l« TS 5 







fcBO =^1-, fl— t> S- rnc ^O 



C.X3 O C'O r-S t^n-, S5 rS— < 



-S-g |.2 >.^ ^|o >,^ ^^ gs 



gfi ^13 '^'b ^S ^t« ^£" S^ 



Ci yj fa i» C^ !>2 •< 



5^ . g <i <5 ^ tf 



W W IZ § <J1 S <5 



IS S ^ ^ ^ <! !> 



