162 AMASTRA, OAHU. 



differs from the others by its rough sculpture and large size. 

 The thickening-up of the parietal callus is probably an old- 

 age feature, which is often correlated with increasing aridity 

 of station. Figured from a co-type in coll. A. N. S. P. 



Section METAMASTRA Hyatt & Pilsbry. 



Imperforate or narrowly rim ate Amastrge with very finely 

 etriate or smoothish embryonic whorls, strong, subhorizontal 

 columellar lamella, the sinus below it narrow and deep, some- 

 what spout-like. Type A. variegata Nc. 



Series of A. variegata. 



Amastra? of compact shape, the spire usually convexly 

 conic, whorls 514 to 6!/o ; apex rather obtuse, the embryonic 

 whorls convex, very finely striate or nearly smooth (except in 

 A. badia) ; later whorls with no dull outer coat of cuticle, 

 usually variegated with opaque buff interrupted bands or 

 streaks ; rather glossy. Outer lip generally thickened within ; 

 columellar lamella strong, subhorizontal, the sinus below it 

 rather spout-like. 



These forms differ from the group of A. rub ens and in flat a 

 chiefly by the spout-like basal sinus of the aperture, produced 

 by an angulation of the whorl around the axis, noticeable be- 

 hind the colurnella in adult shells, while in the neanic stage 

 the basal part of the shell is rather straightly conic. The 

 cuticle, moreover, never has a conspicuous, dull, deciduous 

 layer, as is usual in the inflata group. 



This Oahuan group has been differentiated from Amastrella 

 by the development of variegated coloration in the "middle 

 layer" (not the outer, more or less deciduous cuticle, as in 

 variegated species of Molokai and Maui), and by the peculiar 

 shape of the sinus below the columellar lamella. It com- 

 prises two series of species : Series of A. variegata (see below) , 

 and Series of A. cornea, acutely ovate shells with the spire 

 attenuate, species 41 to 44. 



Mclamastra is here used in a somewhat wider sense than 

 originally limited by the senior author. 



The reticulata series is copiously developed in the eastern 



