AMASTRA, OAHU. 177 



diam. 9 mm. While in some respects it resembles A. decorti- 

 cata and inflata, the texture, short whorls, obtuse summit and 

 downward-bent columellar lamella are features more like the 

 reticulata group. Compare also A. sericea Pfr. It is an iso- 

 lated species. The band mentioned in the description is not 

 invariable, the shell figured having the last two whorls of a 

 rich chestnut color, darkest at the base. Under the lens, fine, 

 superficial and close spiral striae may be traced on the last 

 whorl. 



22. A. THAANUMI n. sp. PL 38, figs. 1, 2. 



The shell is sinistral, imperforate, moderately solid, oblong, 

 having a somewhat silky luster. Spire widely conic with 

 somewhat convex outlines and rather obtuse summit. Em- 

 bryonic whorls marked with faint, very fine growth-striae 

 only; later whorls distinctly striate obliquely, the striae fine 

 and somewhat thread-like. Upper whorls purplish-brown 

 with irregular whitish streaks, the last two whorls covered 

 with a rich dark chestnut cuticle, yellowish next the suture, 

 and deciduous in front of the aperture, showing a glossy 

 light green under layer. Aperture rather oblique, livid or 

 bluish white within, with a whitish callous rim within the 

 dark-edged lip. Columella short, bearing a strong, trian- 

 gular, downward-bent lamella. Parietal callus thin. 



Fig. 1. Length 14.6, diam. 9.5, aperture 7 mm. ; 5% whorls. 



Fig. 2. Length 14.9, diam. 9.5, aperture 7.3 mm. ; 6 whorls. 



Oahu: Kaaawa (D. Thaanum). 



Conspicuous for its sinistral coil. The only living speci- 

 men found is figured. Several dead shells, similar to fig. 2, 

 were taken. These when wet are dull reddish-brown above 

 the periphery, paler or whitish below it, the apex dark purple. 

 By the character of its cuticle this species resembles some 

 forms of A. tristis, but the obtuse summit and short, deep 

 curve below the columellar lamella declare it a member of the 

 reticulata series. Even if dextral, it would stand isolated 

 from other known species. Named in honor of Mr. D. Thaa- 

 num. Co-types to be placed in the Bishop Museum. 



