AMASTRA. 25 



oblique view is given to show the steep ascent of the columellar 

 lamella. 



The Waikolu specimens approach those from Kalamaula 

 in shape. 



A. MORTICINA Pils. Vol. XXI, p. 280. 



Differs from A. umbUicata by its larger size and slightly 

 more regular increase of the spire, that of umbilicata being 

 more attenuated in the upper part. The differences are 

 rather trivial and would be thought unimportant were both 

 forms from one island.. As it is, we are inclined to reduce 

 morticina to a subspecies of A. umbilicata. 



Specimens taken by us in Pleistocene deposits at ' ' Schooner 

 Bay, ' ' on the uninhabited desert island of Kahoolawe, are not 

 distinguishable from the types from Maui. 



A. ULTIMA Pilsbry & Cooke, n. sp. PI. 2, figs. 9, 10. 



The shell resembles A. morticina in figure, but differs by 

 having a noticeably larger umbilicus, and a much weaker 

 columellar lamella. The spire is straightly conic, whorls all 

 convex, those of the embryo smooth, the rest with weak 

 sculpture of uneven and irregular growth-stride . Color from 

 russet to mars brown. Last whorl is compressed around the 

 umbilicus, within which there is a spiral sulcus opposite the 

 columellar lamella. The aperture is rather narrow, angular 

 at both ends, interior colored like the outside ; outer lip thin ; 

 columella vertical, bearing a very low and very oblique lamella 

 which does not quite reach the edge. 



Length 10, diam. 6.1, aperture 5 mm. ; 6 whorls. 



Length 9.9, diam. 6, aperture 4.3 mm. ; 6 whorls. 



Hawaii : Kahuku, Kau, under lava slabs on a nearly naked 

 flow, D. Thaanum. Cotypes 108146 A. N. S. P. and in Bishop 

 Mus. ; also in Thaanum coll. 



This is a species of the greatest interest, as it adds a mem- 

 ber of the ancient group of Amastra umbilicata to the fauna 

 of Hawaii, and in a locality near the southern point of the 

 island. This group of very similar forms is now known from 

 end to end of the archipelago, chiefly in deposits of Pleisto- 

 cene age. 



