TOKNATELLLNA. 



c 1 . Length about 2.2 mm., with 3y 2 whorls; parietal 

 lamella low, ^ of a whorl long ; Sulphur Is. 



T. hataiana, no. 28. 



b 1 . Shell rather slender, thediam. less than half the length, 

 parietal lamella strong; whorls 6; Boiiin Is. 



T. nakadai, no. 27. 



U's of Micronesia (Caroline and Marianne Is.) 



T. subcylindrica, no. 22 ; T. microstoma, no. 23 ; T. moellen- 

 dorffiana, no. 24; T. ponapensis, no. 29. 



Hawaiian Species. 



a. Diameter more than half the length. 



6 . Young usually with one or two palatal folds ; columella 

 strongly sinuous. T. baldwini, no. 5. 



&'. Young without palatal folds. 



c. Shell ovate ; columella weakly sinuous. 



T. mcgregori, no. 6. 

 c 1 . Shell subcylindrical or narrowly ovate. 



T. gayi, no. 30. 

 a 1 . Diameter less than half the length. 



b. Parietal lamella straight in section, not flaring out- 



ward. 



c. Parietal lamella very broad, subhorizontal ; no pal- 



atal ribs in the young; length 2y 2 -3 mm., 4%-5 



whorls. T. ta.ntalus, no. 31. 



r 1 . Parietal lamella moderately developed ; young with 



palatal ribs. 



d. More than 3 mm. long. T. oblonga, no. 20. 



d 1 . Less than 3 mm. long. T. cylindrica, no. 15. 



/>'. Parietal lamella strong, flaring outward, arcuate in 



section. 

 r. Last whorl flattened, with a shallow, broad, per- 



ipheral depression. 

 d. Aperture elongate, shell vitreous. 



T. lanceolata, no. 18. 

 c/ 1 . Aperture small, shell brownish -corneous. 



T. gracilis, no. 19. 



