New Species of Amastra. 23 



obtuse summit. Embryonic whorls increasing very rapidly, con- 

 vex, smooth, under a lens showing no sculpture. The rest of the 

 whorls are convex, separated by a verj' shallow suture, sculptured 

 almost regularly by fine thin growth-wrinkles. The last whorl 

 large, rotund. Aperture oblique, broad, its outer margin very 

 convex and furnished with a delicate lip-rib. Columella narrowly 

 triangular, slightly oblique, with a concave inner margin, its outer 

 margin erect and straight. The columellar fold strong, nearly 

 transverse, terminating rather abruptly close to the outer margin 

 and near the base of the columella. Umbilicus distinctly open, 

 cleft-like. 



Length 9.2, diam. 5.4, apert. 4.3 mm.; 5^3 whls. (Holotype) 



9.8, " 5.4, " 4.4 " 5 



" 8.9, " 5.2, " 4.4 " 5J< " 

 Oahu : Pleistocene of Malaikahana (type locality ) ( vSpalding, 

 Cooke); Kaipapau (Cooke). 



Holotype and cotypes No. 41,982, paratypes No. 41,005, 

 Bishop Museum. 



This is the smallest known species of Amastra from Oahu. 

 Its nearest relative seems to be ^. gulickiana also from Oahu but 

 found further south. A. paidula is easily separated from this 

 species by its much narrower form. It is most easily distinguished 

 from the rest of the Oahuan Amastrse by its small size and pro- 

 portionately large and almost smooth embryonic whorls. Embry- 

 onic shells are of a light horn color with the initial whorl slightly 

 whiter, the largest specimens have about two and one half whorls. 

 They are slightly obliquely angled at the periphery. Above the 

 angle the whorls are very minutely and irregularly striate with 

 growth-wrinkles. The striae are short extending from the angle 

 to near the middle of the whorl. 



A. praeopima, n. sp. 



PI. C. Fig. 8. 



The shell is perforate, dextral, globose, very thin and trans- 

 parent, of a uniform dull brussels-brown color, without a decidu- 

 ous cuticle. Spire short, obliquely triangular, with slightly convex 

 outlines. The embryonic whorls convex, the first smooth, increas- 

 ing rapidlv, the rest increasing more slowly, minutelv transverselv 



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