AM ASTRA, OAHU. 203 



Ahonui shells are deficient in the dull over-layer, which is 

 very than, and therefore not dark enough to contrast strongly 

 with the denuded surface in front of the aperture. 



A small series from Kawailoa, in the Gulick collection, A. 

 N. S. P., is intermediate between inflata and decorticata. The 

 rough sculpture 'and rather dull surface resembles inflata, but 

 the dull, "bloom "-like layer is extremely thin, remaining 

 only in a few shreds, and there is no contrast between the 

 area in front of the aperture and that above the periphery. 

 In these respects the shells resemble decorticata. It would 

 not be amiss to refer these Kawailoa shells to decorticata, 

 which is more widely distributed westward than inftata. 



41. A. RUBIDA Gulick. PL 33, fig. 9. 



S'hell dextral, long-ovate, striated with growth-lines, dilute 

 reddish-chestnut (rarely covered with a blackish epidermis) ; 

 whorls 6, a little convex, the first two smooth, brown ; suture 

 simple. Aperture small, somewhat purple inside. Peristome 

 thin ; columellar fold very thin. Length 18, diam. 9 mm. ' ' 

 (Gulick and Smith). 



Oahu : Kahuku, at the northwest terminus of the main 

 range, on the ground in the forest (Gulick). 



Amastra rubida Gul., GULICK and SMITH, P. Z. S., 1873, p. 

 84, pi. 10, f. 12. 



"It is allied to Am. elliptica Gk., but differs in being more 

 elongate in form, thicker in structure, and for the most part 

 destitute of epidermis. It is always dextral" (Gulick). Mr. 

 Gulick 's figure is copied. 



The senior author writes as follows, having before him a 

 series of 9 shells in the Gulick collection: "This species makes 

 a close approach to rubens in varieties having a reddish- 

 brown middle layer, but 'the periostracuin is not so thick and 

 persistent. The shell is, in fact, not covered by a perios- 

 tracuin except along the suture, and is more uniformly of a 

 pinkish tone, and the aperture in most shells is pink or purple 

 inside. The affinities with decorticata have been noted by 

 Gulick, but the thick opaque shell and transient periostracum 

 appear to place it in the tristis series. A set of shells consid- 



