324 POLYNESIAN NESOPUPAE. 



The two palatal folds are well developed, not very long, either 

 subequal, or the upper somewhat shorter ; the lower decidedly 

 further in. The peristome is expanded and in old shells 

 thickened. Its outer border is bent in a little in the region 

 of the upper palatal fold. Parietal callus thin. 

 Length 2.2, diam. 1.35 mm. ; 5 whorls. 



III. POLYNESIAN, MICRONESIAN AND MELANESIAN SPECIES. 

 Section Nesopupa proper. 



Nesopupae with the surface more or less pitted or pitted- 

 granose, striae with membranous edges often present. Angu- 

 lar and parietal lamellae strong and long, the former curving 

 outward to join the end of the outer lip; inner end of the 

 columellar lamella bent downward ; palatal folds present. 



Nesopupae of the typical group inhabit high islands of all 

 Polynesia and Micronesia, the East Indies and Mascarene 

 Islands, probably also Melanesia, having thus a very wide 

 distribution. 



All of the Polynesian species were considered varieties or 

 subspecies of N. tantilla by Dr. Boettger, whose revision is 

 the main work on them. In the absence of evidence of inter- 

 gradation it seems more logical to recognize the various island 

 forms as species. No doubt many more remain to be dis- 

 covered, as no adequate search has been made for the minute 

 shells of Polynesia. Probably arboreal species will be found, 

 as in Hawaii. 



(Polynesia.) 



Beck mentioned two undescribed species. Alcua pitca-irnensis 

 Beck, and Alaea millium Beck, Index Molluscorum 1837, p. 85. 

 Pitcairn Island. Names and locality only. 



21. NESOPUPA TANTILLA (Gould). PL 30, figs. 1 to 4. 



Shell very minute, of an oval form, obtuse at summit, and 

 composed of about four convex whorls, of which the upper ones 

 are irregularly marked with delicate longitudinal bars, and 

 the lower one, under a magnifier, appears to be roughened by 

 minute, irregular granulations. Color whitish. Aperture 



