30 AMASTRA. 



shells more like var. dispersa. Probably A. conspersa is not 

 separable from typical reticulata. 



A. r. dispersa was taken by Thaanum in Haleauau, up to 

 19 mm. long, the largest 10.5 mm. in diameter. It is also 

 common on the western ridge of Popouwela where the shells 

 are extraordinarily variable in size, shape and color. 



A. RETICULATA VESPERTINA P. & C., n. Subsp. PI. 2, fig. 17. 



The shell is small, perforate, oblong-conic or coni-cylindric, 

 irregularly striate, not spirally striate ; fossil, but the freshest 

 shells show traces of numerous dark spiral bands. Aperture 

 only slightly oblique, angular at both ends. Outer lip obtuse, 

 somewhat thickened within. Columellar lamella prominent 

 and subhorizontal. 



Length 12, diam. 6.5, aperture 5.7 mm. ; 5% whorls. 



Length 13, diam. 6.9, aperture 6 mm. ; 6 whorls. 



Oahu: Kawaihapai, in soil of a plowed field between the 

 railroad and the bluff, cotypes no. 108980 A. N. S. P. and in 

 the Bishop Museum. Pilsbry and Cooke, 1913. 



This form closely resembles A. transversalis bryani of the 

 Punchbowl and Diamond Head. Both seem to be depauper- 

 ate races, possibly in response to the increasing aridity which 

 finally wrought their destruction. A. r. vespertina lived on 

 the coastal plain near the railroad, about a half-mile from 

 the first bluff of the Waianae range. It doubtless dates from 

 the humid stage of the Pleistocene or the early human period, 

 when forest extended down to the present sea level. 



A. EXTINCTA (Pfeiffer). PI. 7, fig. 5. 



Vol. XXI, p. 159. A figure of the type in the British 

 Museum is given. It seems to be a species of the A. cornea 

 group, and should be looked for in the superficial deposits of 

 Kona. The figure suggests a shell which had succumbed to 

 arid environment. 



Section AMASTRELLA. Oahu. 

 A. RUBENS (Gld.). Vol. XXI, p. 192. 



Mokuleia, Haleauau and Makaha (Thaanum). A set from 

 Mt. Kaala has the rich chestnut cuticle almost entire, the 



