TORNATELLINA. 137 



c 1 . Last whorl convex, without depression. 

 d. Columella strongly twisted in the adult. 



T. polygnampta, no. 16. 

 d l . Columella weakly twisted. T. peponum, no. 17. 



Polynesian Species. 

 %. Shell oblong- turri ted, of 9-10 whorls; Rapa. 



T. turrit a, no. 51. 

 % l . Shell oblong-conic or ovate-conic, of 7 whorls or less. 



b. Columellar lamella superposed upon the spiral fold ; 

 at least in the young ; two palatal plicae or successive 

 pairs of teeth, sometimes wanting in the adult 

 stage. 



c. Length 4y 2 to 5 mm., diain. 2 to 3 mm., whorls 6-7 ; 

 usually two palatal teeth or short, entering plicae. 

 T. bttamcllata, no. 1 ; T. hidalgoi, no. 2 ; T. gouldi, 

 no. 4. 



c 1 . Smaller, length 2.5 to 3, diam. 1 to 1.6 mm. ; whorls 

 5-6. Columella having palatal teeth in pairs or in 

 one spiral series, sometimes wanting in the adult 

 stage. 



d. Columellar lamellae 3, an oblique fold above 

 and a small denticle below the median la- 

 mella. 



e. Columellar lamella prominent in a front 

 view; usually having palatal teeth in 

 pairs. T. perplexa, no. 7. 



e l . Columellar lamella immersed; a low cal- 

 lous streak in the palatal region. 



T. societatis, no. 10. 



d 1 . One prominent columellar lamella, with a more 

 or less obvious fold above it, but no denticle 

 below it. 

 e. Whorls convex; columellar lamella deeply 



placed. 

 /. Length 2.8, diam. 1.6 mm. ; Fiji Is. 



T. columellaris, no. 11. 

 f 1 . Narrower, length 3.2, diam. 1.5 mm. 



T. nitida, no. 8. 



