LYROPUPA. 255 



mellar lamella strong, almost transversely placed upon the 

 columella. Upper palatal fold small, shorter than the lower, 

 and not quite reaching the inner margin of the peristome; 

 the entire length of both seen in a front view. 



Length 2.8, diam. 1.6, apert. 1.1 mm.; 5% whorls. 



East Maui: Ukulele, type loc. (Forbes). W. Maui: Mauna- 

 hooma (Cooke). Type 11049 Bishop Museum; paratypes 

 12639, Bishop Museum and 119465 A. N. S. P. 



Only five adult specimens of this race have been seen, four 

 from the type locality, one from West Maui. 



The shell is less fusiform than L. spaldwgi, darker colored, 

 the base less produced, and the palatal folds shorter; but it 

 differs conspicuously by the single broad and deep furrow on 

 the back of the last whorl. 



Section Mirapupa C. & P., n. sect. 



The shell is dextral ; the angular lamella is high and rather 

 long; the surface is ribbed and minutely striate spirally (when 

 unworn). Other characters as in Lyropupa. Type Lyro- 

 pupa perlonga (Pse.). 



Typically the lower palatal fold is short, and there are two 

 tubercles forming a vertical barrier under the inner end of 

 the upper palatal fold; but some species have the palatals as 

 in typical Lyropupae. 



Except in being dextral, these shells resemble the typical 

 Lyropupae. 



On all of the Hawaiian islands, these are Lyropupae chiefly 

 of the arid lower zone, probably nowhere found in the zone 

 of humid forest. They live under stones. Owing evidently 

 to increasing aridity since the Pleistocene, many forms have 

 become extinct, and the others are local and infrequently found 

 as living snails. They are among the most abundant Pleisto- 

 cene and Holoceue fossils, in many places to be collected by 

 hundreds or by thousands. 



The peculiar feature of most Mirapupae is the inner barrier 

 formed of two short folds or tubercles below the inner end of 

 the upper palatal fold, as in pi. 25, fig. 15 and other figures. 

 These internal tubercles are the enlarged and isolated inner 



