310 AMASTRA, HAWAII. 



6 1 . Diam. less than two-thirds the length; length 14 



to 20 mm. A. flavescens, no. 109. 



a 1 . Embryonic whorls very finely, sharply striate; shell 



thin, with brown or black cuticle (wanting in fossil 



forms) ; lip thin. 



&. Openly umbilicate, broadly conic, subangular 

 peripherally ; 21x16 to 23x18 mm. ; fossil. 



A. senilis, no. 105. 

 6 1 . Perforate. 



c. Ovate-conic, diam. more than half the length, 

 the last whorl usually slightly angular, 

 with black cuticle. Length 13 to 14, diam. 

 8 mm. or smaller. A. melanosis, no. 106. 

 c 1 . High-conic, the last whorl rounded; 15.5x8 

 mm., with 6% to 7 whorls; fossil. 



A. conica, no. 107. 

 c 2 . Similar but smaller, dull brown; recent. 



A. c. gyrans, no. 107a. 

 c 3 . Yellow streaked with chestnut ; 15x7 mm. 



A. c. kohalensis, no. 107b. 



c 4 . A little broader, length 15.3 to 18, diam. 9 

 mm. ; whorls 6 to 7 ; fossil. 



A. fossilis, no. 108. 



Section HETERAMASTRA Pilsbry (p. 283). 



104. A. SINISTRORSA Baldwin. PL 49, figs. 6, 7. 



Shell imperforate, sinistral, lanceolate, rather thin. Spire 

 long, with straight outlines. First half-whorl smooth, convex, 

 forming an obtuse apex; next whorl flattened, subacutely 

 carinate near the base, sculptured with fine, curved riblets; 

 on the next whorl the carina weakens and then disappears, 

 and the riblets become finer and closer. Later whorls are 

 moderately convex, rather rudely sculptured with growth- 

 wrinkles, not angular above the impressed suture. Aperture 

 strongly oblique, the outer lip thin. Columella straight, il 

 edge narrowly reflexed and adnate above; bearing a smal 

 and very oblique fold. Length 14.7, diam. 6.2, aperture 5. r 

 mm. ; 6!/2 whorls. 



