232 AMASTRA, LANAI. 



AMASTR.E OF LANAI. 



The Amastrae of Lanai are closely related to those of Molo- 

 kai. The biplicata series is especially developed, and the as- 

 simiUs series of eastern Molokai and Maui is absent. Amas- 

 trella and Cyclamastra have not been found, but perhaps they 

 may turn up as fossils, or even recent, as the island has not 

 been very thoroughly explored. Heteramastra is represented 

 by one species. 



Key to Amastrce of Lanai. 



a. Shell sinistral. A. fraterna, no. 55. 



a 1 . Shell dextral. 



6. Shell globose-conic, 12x8.3, aperture 6.8 mm. 



A. nucula, no. 57. 



6 1 . Ovate-conic, oblong or turrited; aperture not over 

 half the length. 



c. Small, banded, with costate and carinate 



apex; 11.6x6 mm. A. pusilla, no. 56. 



c 1 . Large (over 18 mm.), embryonic whorls 



handsomely costate and usually carinate. 



d. Whitish, fleshy or purplish under a 



fragmentary brown or blackish cuticle ; 



length 25 to 36 mm. A. magna, no. 58. 



d 1 . A white peripheral band, spire brown; 



smaller. A. m. ~balteata, no. 58a. 



d 2 . Yellow under a deep brown cuticle; 



aperture yellow; length 23 to 25 mm. 



A. aurostoma, no. 59. 



d 3 . Banded with brown; cuticle yellowish, 

 dark behind the lip. 



A. gray ana, no. 60. 



d*. Yellow under the blackish cuticle; 



whorls shorter; aperture pink or red. 



A. rubristoma, no. 61. 



c 2 . Shell oblong-conic or turrited, the embryonic 

 whorls finely striate ; aperture usually pink ; 

 columella often biplicate. 



