206 AMASTRA, OAHU. 



lique, white inside. Peristome 'has a rather strong rib within. 

 Columella short, rather widely dilated, bearing a strong spiral 

 l-amella. Parietal callus thin 'and transparent. The axis is 

 slender and sinuous, widening upward in each whorl. The 

 superposed lamella penetrates a little less than one whorl. 



Length 18, diam. 11, length of aperture 9 mm. Palolo. 



Length 18, diam. 10.5, length of aperture 8.5 mm, Palolo. 



Length 16.5, diam. 10.2, length of aperture 8.5 mm. Palolo. 



Oa.hu, valleys of the southeastern slope of the main range : 

 Keawaawa, Makiki, Waialae, Palolo, Nuuanu (Gulick) ; Kalihi 

 (Oleson coll.) ; Niu and Aeia (Cooke). 



Helix tristis FEE. (Prodrome, p. 60, undescribed), Voyage 

 autour du Monde de 1'Urande et la Physicienne, Zoologie, p. 

 482, pi. 68, f. 6, 7 (1824) . Bulimus tristis PFR., Symbolse, ii, 

 p. 52.Achatinella tristis PFR., P. Z. S., 1845, p. 89 ; Monogr., 

 ii, p. 240; iii, 456; dv, 444; vi. 177; Conchyl. Cab., p. 286, pi. 

 67, f. 10, 11. REEVE, Conch. Icon., vi, pi. 5. f. 37 (1850).- 

 THWING, Orig. Descriptions, p. 143, pi. 3, f. 13. Amastra 

 tristis PEASE, P. Z. S., 1869, p. 649. BALDWIN, Catalogue, p. 

 10. Achatinella fuliginosa GOULD, Proe. Boat. Soc. N. H.. ii, 

 1845, p. 28. 



The specimens from Keawaawa. collected by Gulick, are all 

 dead shells. 



The outer chocolate or blackish cuticle is unusually per- 

 sistent in one lot from the lateral ridge of Nuuanu (no. 530 

 Cooke coll.), and in those from Tantalus (pi. 32, figs. 6, 7). 

 A similar black form occurred at Aiea, far to the west and 

 widely separated from other known colonies, the nearest being 

 in Kalihd. 



One of the lots from Niu consists of dwarfed abnormally 

 shortened shells (pi. 32, fig. 10), -the last whorl more or less 

 angular in front, the spire somewhat telescoped into the last 

 \vhorl in part of the shells. One specimen has several spiral 

 grooves cutting the growth-wrinkles on the last whorl, as in 

 A. undata. 



In Nuuanu shells the cuticle may be either black and in 

 sihreds, or nearly continuous and of a rich chestnut color (fig. 

 5). The size of these chestnut shells varies widely, length 

 from 15 to 19 mm. Figures 1 to 4 are from Palolo shells. 



