New Species of Amastra. g 



in Baldwin's species. The diameter of the perforation is less in 

 proportion than in A. antiqua or its variety A. a. kawaihapaiensis . 

 Only four specimens of this species were taken by Mr. Thaa- 

 num in a very rich pocket of fossiliferous earth. The pocket 

 contained about a bushel of earth and in it were thousands of shells 

 and shell fragments. 



A. modicella, n. sp. 



PI. A. Fig. 7. 



The shell is openly perforate, dextral, thin, fragile. In its fossil 

 state of a pale brownish- white. The embryonic whorls are 

 minutely, though distinctly, striate, convex. The rest of the whorls 

 are convex, sharply and irregularly striate with growth-wrinkles, 

 becoming coarser on each succeeding whorl. Sutures rather deep. 

 Aperture rather large and broad for a shell of its size, with a very 

 convex outer margin, not distinctly biangular as in most of the 

 species of this subgenus. The columella is narrowly triangular 

 with a straight outer margin. Columella fold very weak, diago- 

 nal, and extending nearly to the base of the columella. Umbilicus 

 minute, nearly circular, with a rounded edge. 



Length 9.3, diam. 5.4, apert. 4.1 mm.; 5^2 whls. (Holot}'pe) 

 " 11.0, " 5.6, " 4.4 " 6 " 



Hawaii: Waikii station, in the land of Waikoloa, about 

 6,000 feet elevation. 



Holotype and cotype No. 41,969, paratypes No. 41,970, Bishop 

 Museum. 



This species is intermediate between A . ultima and A . fragilis, 

 the latter from the island of Molokai. It differs from the former 

 by its much smaller umbilicus, slightly more convex spire and the 

 aperture is not as distinctly biangular, Besides the surface is 

 rougher and more deeply sculptured with growth-striae. It agrees 

 with the latter species in the size of umbilicus and form of aper- 

 ture. It differs, however, in its less attenuate spire, greater pro- 

 portional breadth and more compact form. 



The specimen from which the second set of measurements was 

 taken is much larger than any of the other specimens and differs 

 considerably from them. It is a loosely coiled shell with an indis- 

 tinct suprasutural angle on the penultimate whorl. In this speci- 

 men the columellar fold is very weak. It is represented by a faint 



line which does not reach the margin of the columella. 



[227] 



