A^ew Species of Aviastra. 19 



The embryonic whorls are elongate, nearly flat, very faintly and 

 minutely striate. The following whorls are indistinctly flattened 

 above, convex below and indistinctly shouldered above the sutures, 

 rather irregularly sculptured with oblique coarse growth-wrinkles. 

 The last whorl is rounded, tapering towards the base aud slightly 

 contracted around the umbilicus. Aperture somewhat oblique, 

 contracted slightly above, with its outer margin thin and regularly 

 strongly arched. Columellar narrowly triangular, its inner margin 

 slightly oblique, the outer margin thin and slightly arched above 

 the umbilicus. Columellar fold not strong, nearly transverse, 

 terminating very gradually at the outer margin of the columella. 

 Umbilicus subcircular, its margin rounded and slightly contracted, 

 enlarged within. 



Length 13.7, diam. 8.0, apert. 5.6 mm.; 7 whls. (Holotype) 



" II. 8, " 7.2, " 5.2 " bYz " 

 Hawaii : Pleistocene at Kapulehu, about three miles north 

 of Huehue and nearly the same elevation (A. Gouveia). 



Holotype No. 41,976, paratypes No. 41,977, Bishop Museum. 

 This species is closely related to the following A. pagodula. 

 Immature specimens of both species are similar though the adults 

 have an entirely different appearance. In an immature specimen 

 of A . fragosa there is a distinct peripheral keel not quite as strongly 

 developed as in specimens of A. pagodula of about the same age. 

 The immature specimens of both species are quite separable as the 

 spire of A . fragosa is longer, sharper and slightly concave-conic. 

 In some of the adult specimens of this species there is a slight 

 tendency to form an indistinct angle at the periphery. When this 

 character is present, the margin of the aperture is not modified as 

 the angle disappears before reaching the aperture. 



Embryonic specimens of both species exhibit about the same 

 characters. Those of A. pagodula are slightly broader in propor- 

 tion to their length the whorls increasing more rapidly and not as 

 compact or closely coiled as in A. fragosa. 



A. pagodula, n. sp. 



PI. H. Fig. 4. 



The shell is narrowly umbilicate, dextral, conic, thin, in its 

 fossil state of an ochraceous-orange on the upper whorls, the last 



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