204 AM ASTRA, OAHU. 



ered by Gulick to be passage forms into decorticata are five in 

 number, and of these one is a true decorticata with entire 

 periostracum and acute apex ; the four others have the typical 

 colors and periostracum of this species, combined with a 

 blunter apex, shorter, stouter spires and lighter-colored aper- 

 tures which may be considered as belonging to such hybrids 

 as could 'be called rubida-elliptica. It appears to me to be 

 therefore an elliptica form derived from elliptica.'" 



42. A. ELLIPTICA Gulick. PL 34, figs. 17 to 23. 



"Shell dextral, ovate, hardly shining, lightly striated with 

 growth-lines. Whorls 5%, convex, the first 4y 2 brownish- 

 corneous, and the last whorl paler, clothed with a dark oli- 

 vaceous epidermis which is partly worn from the front of the 

 last whorl. Spire somewhat turrite, suture simple. Aper- 

 ture white, rose-tinted in front (sometimes white) ; peristome 

 thin, very slightly thickened within. Columella arcuate, the 

 lip-ends joined by a thin callus, provided with a compressed 

 subbasal tooth. Length 15, diam. 8.5 mm." (Gulick). 



Oahu : Waialei, type loc. ; also in Kahuku and Hanula, and 

 rarely in Kawailoa, on the ground in 'the forest (Gulick). 



Amastra elliptica Gk., in GULICK and SMITH, P. Z. S., 1873, 

 p. 83, pi. 10, f. 15. SYKES, Fauna Hawiaiiensds, 1900, p. 336. 



"It is allied to A. rubens Gld. and A. decorticata Gk., but it 

 is thinner, smaller, and darker in color than the former, and 

 it has a more convex spire than the latter" (Gill.). 



A. elliptica differs from decorticata and its allies by the 

 strong development of the outer layer of epidermis. On the 

 front of the last whorl it is light olive-brown with many un- 

 equal blackish streaks ; on the back the streaks coalesce into a 

 more or less continuous black area on the last fourth of the 

 last whorl. The under layer of cuticle, exposed in front of 

 the aperture, is pale yellow. Dead shells which have lost all 

 of the cuticle are reddish on the spire, the last whorl white, 

 or in 3 out of 40 from Waialei the last whorl is white above, 

 reddish below the periphery. One of these denuded shells is 

 drawn in pi. 34, fig. 22. Normal shells of the same lot are 

 shown in figures 20, 21. 23. 



