New Species of Aviastra. 7 



This extremely rare and interesting species is entirel}- distinc 

 from an}' other species of Amastra. The Pleistocene deposits in 

 Manoa are rather interesting as the shells do not occur in layers 

 as in most deposits but in rather small pockets, containing from a 

 few cc. to maybe half a liter. These pockets are literally full of 

 shells, mostly in fragments, and belong to a number of genera. 



A. thtirstoni (W&txs from all the other species of Cydamastra by 

 its proportionately long and slender spire and distinct plicate sur- 

 face. It is not closely related to any of the known Oahuan species, 

 but appears to be related to A. fragilis of Molokai, with which it 

 agrees in having a narrow perforation and attenuated spire. It 

 differs, however, in having more whorls, the spire is proportion- 

 ately more attenuate and the surface more distinctly plicate. 



A. gouveii, n. sp. 



PLC. Fig. 3. 



The shell is narrowly perforate, conic, very thin, translucent, 

 irregularly striate, covered with a uniform dresden-brown epider- 

 mis, slightly lighter below the periphery. Spire narrowly conic, 

 with an acute apex. Whorls nearh- 7, covex ; the embryonic dis- 

 tinctly very finely but regularly striate ; the rest irregularly striate, 

 the striae arcuate, blunt; the last whorl rather short, rotundate, 

 bluntly angulate at the margin of the perforation. Aperture rather 

 broad, slighth' oblique, with its outer margin almost regularly 

 cur\-ed, hardly angulate at its junction with the columella, and 

 with scarcely any thickening along the outer margin of the peris- 

 tome. Columella straight, narrow, arched above the narrow com- 

 pressed perforation, furnished near its base with a minute deeply 

 seated oblique fold. 



Length 12.4, diam. 6.2, apert. 5.0 mm. (Holotype) 



Oahu : Wailupe, east side a little more than half way up the 

 ridge, on the dead leaves of Ki (Cordyline termhialis) 



Holotype No. 40,547, paratypes No. 40,54^, Bi.shop Museum 

 and in Gouveia collection. 



A . goiiveii is very closely related to A. nmbilicata Pfr., and is 

 undoubtedly derived from the same stock, being probably, a high 

 altitude relative of this lowland species. There are a number of 



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