192 AMASTRA, OAHU. 



Oahuan Amastrge. The other groups, Metamastra and Para- 

 mastra, have diverged further from the ancestral stock. 



One species, A. tristis, sometimes has rather coarse low ribs 

 on the second embryonic whorl, the apex being more conic 

 than in most other species, not unlike that of Kauaia. A, 

 tristis, together with some other Oahuan species, was grouped 

 with the Molokaian pullata and violacea series by the senior 

 author (in MS.) . The shape of the embryonic whorls and the 

 maculation of the neanic whorls in many individuals are like 

 A. badia; the incised spiral striae are also characteristic of 

 undata, transversalis and others of the group to which badia 

 belongs ; so that A. tristis seems to be a somewhat generalized 

 or synthetic species; yet its chief relationship is with the 

 in flat a group. 



35. A. RUBENS (Gould). PI. 32, figs. 16, 17, 19, 20, 21. 



' ' Shell elongate-ovate ; thick ; straw- colored, the apex chest- 

 nut, anterior end reddish. Whorls 6, convex; suture im- 

 pressed ; covered here and there wth brown epidermis. Aper- 

 ture ovate; lip simple, thickened within, roseate, the throat 

 white; fold thin; imperf orate. Length %, diam. % of an 

 inch. A plain species, but well marked by its colors, especially 

 by that of the aperture ' ' ( Old. ) . 



"Animal dark slate, as long as the shell, tentacles black, 

 bottom of foot and mantle brown. Excessively timid and 

 lives buried under leaves and other decaying vegetation" 

 (Newcomb). 



Oahu, Waianae range: West mountains (Newcomb) ; Wai- 

 anae (Gooke, Baldwin) ; Kaala (Baldwin) ; Kukuiala and 

 Mokuleia ( Gulick) . Varieties in the eastern range, see below. 



Achatinella rub ens GLD., Proc. Bost. Soc. N. H., ii, Jan. 

 1845, p. 27. PFR., Monogr., ii, p. 240 ; iii, 459 ; iv, 552 ; vi, 

 180 (exclusive of var. b, = A. mastersi Nc.). REEVE, Conch. 

 Icon., vi, pi. 6, f. 42&. NEWCOMB, Ann. Lye. N. H. of N. Y., 

 vi, p. 314. BALDWIN, Catalogue, 1893, p. 9. 



The first half- whorl is smooth; then very fine, sharp and 

 close and weakly arcuate longitudinal strias appear, contin- 

 uing for two whorls, after which comparatively coarse but 



