1903.] XATUIIAL SCIENCES OF PHILADELPHIA. 791 



The radula has about 15.8.1.8.15 teeth. The central tooth in each 

 row is small and unicnspid. The laterals are bicuspid; the inner ones 



have the inner cusp wide and obtuse or slightly emarginate, evidently 

 composed of entocone + mesocone. The two cusps become subequal 

 on the outer lateral teeth. The inner marginal teeth have three 

 cusps, the outer ones four, by splitting of the entocone. 



The jaw is arcuate, with small lateral appendages as usual in Limncea. 

 It is smooth. 



The teeth of this snail differ from those of Holarctic species of Lim- 

 ncca in the structure of the laterals, but the radula is not that of the 

 Planorhina\ The dentition is known in so few Limnseid species out- 

 side of Europe and the United States that no useful comparisons of this 

 peculiar Hawaiian type can be made. The animals as contracted in 

 formalin resemble LimncEa externally, having short, wide tentacles and 

 a short foot. 



