12 Nciv Species of Aviastra. 



cylindrical, in some cases, the surface showing an indication of 

 indistinct malleation. The aperture is slightly oblique, rather nar- 

 row, with a regular convex outer margin, furnished with a thick 

 strong lip-rib. Columella short, almost perpendicular. Columel- 

 lar fold subniedian in position, rather weak, terminating gradually 

 close to the margin of the columella. 



Length 12.5, diam. 6.7, apert. 5.8 mm.; 6^ whls. (Holotype) 

 13.6. " 7.2, " 5.7 " b^z " 

 10.8, " 6.2, " 5.0 " dH " 



Kauai: Pleistocene of Koloa (Stokes); Mahalepu and Kipu- 

 kai (Cooke). 



Holotype and cotypes No. 41,997, paratypes No. 35,809, 

 Bishop Museum. 



Ver}^ abundant in the Pleistocene deposits under the sand 

 dunes of all the above localities, associated with, but not as abund- 

 ant as A. si?)nlaris. This form is for the present placed as a 

 variety of A. riigulosa, though it may prove ultimately to be 

 worthy of specific rank. The shells of this variety are for the 

 most part slightly longer and considerably narrower than those of 

 A. riigulosa or any of its varieties. The narrow extended embry- 

 onic whorls are also a distinctive character. This variety is 

 geographically related to A. r. iiormalis, live specimens of which 

 are still abundant on the northern slopes of the mountain range, 

 which cut off the southern beaches from the rest of Kauai. 



A. rugulosa var. annosa, n. var. 



PI. A. Fig. 9. 



The shell is perforate, dextral, elongate-conic, rather thin, 

 in its fossil state of a dull tawny olive color. The embryonic 

 whorls are nearly smooth, the other whorls (due to the slightly 

 worn state of all the specimens) are indistinctly obliquely and 

 irregularly sculptured with growth-wrinkles. The aperture is 

 diagonal, oblique, slightly contracted above, with a ver}- convex 

 outer margin, furnished with a thick lip-rib. Columella narrowl}^ 

 triangular, slightly bent backwards, its outer margin indistinctly 

 thickened and united with the outer margin of the peristome by a 



thin parietal callus. Columellar folds weak, oblique, terminating 



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