AMASTRA, MAUI. 279 



AMASTR^E OF MAUI. 



The Amastrae of Maui are in the main smaller than those 

 of Molokai and Lanai, the magna and 'biplicata series being 

 absent here, while globose Cyclamastrce, wanting in the other 

 two islands, are present. Otherwise the species are closely 

 related to those of Molokai, and in some cases hardly separ- 

 able. 



The Amastrae of the eastern and western mountain masses 

 of Maui are specifically distinct but so closely related that 

 we have reason to believe that the present isolation by a 

 treeless, grassy area has been effected in Pleistocene time. 

 The two areas apparently existed as a continuous forested 

 tract up to and probably for a short time after the separation 

 from Molokai. 



The island is therefore by no means so fundamentally dual 

 as Oahu, where distinct groups of Amastrae were evolved on 

 the two areas. 



Luxuriant native forests occupy the higher part of West 

 Maui and they are especially extensive on the windward 

 (northeastern) slopes of Haleakala, East Maui, where many 

 new forms will doubtless be found, for this almost impene- 

 trable forest remains unexplored and its molluscan life is 

 unknown, as Baldwin writes. On the western slope of Halea- 

 kala, in Kula, where most of the Newcomb and Gulick species, 

 and the specimens in the older 'collections were taken, the 

 forests are in large part dead or dying. 



Key to Amastrce of Maui. 

 I. Shell sinistral (see Heteramastra, p. 283). 

 II. Shell dextral. 



a. Shell umbilicate (Cyclamastra) . 



&. Globose-conic, diam. about two- thirds the length 



or more. 



c. Periphery rounded. A. obesa, no. 84. 



c 1 . Periphery angular. A. agglutinans, no. 85. 



6 1 . Ovate-conic, diam. not much over half of the 



length. A. morticina, no. 83. 



a 1 . Shell imperforate or nearly so (Amastra). 



