AMASTRA, LANAI. 243 



ered by a thin, much- worn blackish-brown cuticle. The api- 

 cal whorls are reddish, worn in all of the specimens, but they 

 seem to show traces of costation; the keel, if any, is nearly 

 or quite concealed in the suture. The subsequent whorls are 

 weakly marked with growth-lines, rather glossy, and strongly 

 convex. Aperture bright pink within in the two larger shells, 

 merely pinkish-white in the smallest, The pink lip-rib is 

 strong or rather weak. The well-developed columellar fold is 

 median and quite oblique. 



Length 19.3, diam. 11.7, aperture 9.2 mm. ; 6% whorls. 



Length 19.3, diam. 11.4, aperture 8.9 mm.; 6y 2 whorls. 



Length 17, diam. 11, aperture 8 mm. ; 6% whorls. 



Series of A. biplicata. 



Embryonic shell purple-brown, very finely sharply striate, 

 the whorls somewhat convex. Adult stage oblong or turrite, 

 partly covered with a blackish deciduous cuticle, which is 

 variegated on the intermediate whorls. Columella with one 

 or tiuo folds and, with the parietal callus, usually pink. 



The sculpture of the embryonic shell is stronger than in 

 the Oahuan group of A. turritella, and the apex is somewhat 

 more pointed, but the resemblance is perhaps indicative of 

 relationship. It should be noted that in the turritella series 

 also there is a tendency to form a second 'columellar fold, in 

 rare individuals. The variegated cuticle of the neanic stage 

 allies the biplicata group to typical Amastra of Lanai and 

 Molokai, from which it differs by the convex, striate, not cos- 

 tate, embryonic whorls a character variable in Amastra. 



Species are known from Lanai and Molokai. Data for 

 mapping the range of the Lanaian forms are wanting. We 

 have as yet only scanty information on the details of distri- 

 bution in this island. 



62. A. BIPLICATA (Newcomb). PL 17, figs. 1 to 6. 



Shell dextrorsal, elongately cylindrical ; whorls 7, rounded, 

 longitudinally strongly striated ; suture deep ; aperture small, 

 subovate ; inner lip rather callous ; columella biplicate ; outer 



