24 New Species of Amastra. 



sculptured with rather fine sharp striae and encircled by about six 

 narrow parallel furrows. The following whorls distinctly marked 

 with almost regular close transverse growth-wrinkles. The last 

 whorl large, swollen, rotund. Aperture very large, more than 

 half the length of the shell, slightly oblique, with a very convex 

 outer margin which is slightly thickened near the base of the 

 columella. Columella straight, narrow, its outer margin free and 

 arched over the perforation. Columellar fold basal in position 

 rather strong, slightly oblique, terminating very abruptly close to 

 the margin of the columella. Perforation narrow, cleft-like. 



Length 10.7, diam. 7.8, apert. 6.1 mm.; 5 whls. (Holotype) 



" 12.7, " 8.6, " 6.7 " 5 y 2 - 



Oahu : Waiahole at the crest of the Koolau range where the 

 trail crosses the ridge (Cooke). 



Holotype No. 41,983, cotype No. 41,984, paratypes No. 23,590 

 and 23,612, Bishop Museum. 



The latter measurements given above are of an old dead shell. 

 In this specimen the columella is bent obliquely backwards, the 

 outer margin of the aperture is furnished with a thick strong lip- 

 rib and there is a thick parietal callus. The characters of the 

 embryonic whorls given above were taken from an immature shell 

 with four whorls. In this specimen there is an oblique angle at 

 the periphery. The columella is straight and the columellar fold 

 is more centrally placed than in adult shells. A. praeopima is 

 easily distinguished from all the other Oahuan species of Amastra. 

 Its closest relative is undoubtedly A. gulickia?ia. The latter has, 

 however, a thicker and less globose shell, much less distinctly and 

 sharply striate and the columella is shorter. 



A. forbesi, n. sp. 



PI. B. Fig. 8. 



The shell is imperforate, sinistral, elongate-conic, thin, in its 

 fossil state pure white. Outlines of the spire regularly, slightly 

 convex, summit rather sharp. Embryonic whorls slightly convex, 

 indistinctly minutely striate. The rest of the whorls slightly con- 

 vex, finely striate with growth- wrinkles. The last whorl elongate, 

 subcylindrical, rather coarsely striate, descending rapidly near the 



aperture, forming a rather oblique suture. The aperture is rather 



[242] 



