AMASTRA, OAHU. 161 



perforation penetrating almost to the apex ; solid, elongately 

 ovate, apex subacute ; surface sculptured with, rude, irregular 

 lines of growth, the apical whorls smooth. Color of the living 

 shell unknown. Whorls 6, convex; suture well impressed. 

 Aperture a trifle oblique, sublunate; peris-tome thickened 

 within, columellar margin adnate, slightly expanded over the 

 umbilicus, extremities somewhat converging and united by a 

 thick parietal callosity; columella flexuous, terminating in a 

 narrow plait. Length 20, diam. 12 mm." (Baldw.). 



Oahu: Ewa. 



Amastra antiqua BALDWIN, Proc. A. N. S. Phila., 1895, p. 

 233, pi. 11, f. 47. 



"We received this species from Prof. A. B. Lyons, of Oahu 

 College. He reports that he found at Ewa a singular accu- 

 mulation of these and other fossil land shells, huddled to- 

 gether in one spot in a bed of soft tufa-like material, at an 

 altitude not far above sea-level. The existence of living ex- 

 amples of this and the following species now, or within any 

 recent period, is highly improbable " (Baldwin). 



The sculpture consists of coarse, unequal wrinkles separated 

 by finely, irregularly striate intervals, the embryonic shell ap- 

 pearing smooth in the fossil examples. It is narrowly um- 

 'bilicate, rather than "perforated," as described by Mr. Bald- 

 win, the umbilicus being nearly 1 mm. wide. The spire is 

 slightly contracted near the summit. The peristome is obtuse 

 with a callous rib within. There is a low, oblique nodule or 

 callous ridge on the parietal wall some distance within, above 

 and rather near the origin of the columella. The parietal 

 callus is rather thick at the edge in adult shells. Two speci- 

 mens of the type lot measure : 



Length 20.3, diam. 13, aperture 10 mm., whorls 6. 



Length 18, diam. 11.5, aperture 8.2 mm., whorls 6%. 



This species is probably related to the group of smaller 

 forms comprising A. similaris Pse. (Kauai), A. hartmani Nc. 

 (Oahu) and A. morticina Pils. (Maui). In all of these forms 

 the umbilicus is large for an Amastra, the embryonic whorls 

 are smooth, the columellar lip free and not much dilated, and 

 the columellar lamella rather small and oblique. A. antiqua 



