TORNATELLIDES OF HAWAIIAN ISLANDS. 217 



From the other species of Tornatellides it is easily recog- 

 nized by its strong, slightly oblique columellar folds. These 

 folds are nearly equal in size, usually the upper is very 

 slightly stronger than the lower. In the type specimen the 

 lower fold is 0.09 mm. in height. 



An immature specimen with over 5% whorls has a rather 

 strong, thick parietal lamella 0.2 mm. in height. The upper 

 columellar fold is 0.13, the lower 0.2 mm. in height (fig. 4). 



An embryonic specimen is minutely perforate ; the upper 

 11X> whorls are smooth, the next whorl minutely transversely 

 striate. Only the lower columellar fold is present. It is 

 deeply seated and oblique. The parietal lamella is very 

 strongly developed. 



In the form from the western ridge of Popowela, which 

 may be called var. anisoplax P. & C. (pi. 47, fig. 7), the lower 

 columellar lamella is decidedly larger than the upper in fully 

 adult specimens, as well as in the neanic stage. Type no. 

 108899 A. N. S. P., cotype in B. P. B. Mus. 



23. T. DIPTYX P. & C., n. sp. PI. 47, figs. 8, 9. 



The shell is ovate-turrited, minutely umbilicate, brown, 

 smooth ; outlines of the spire straight, the apex obtuse. Whorls 

 nearly 6, rather convex, the last short. Aperture small, ovate. 

 Parietal lamella very broad and at least a half-whorl long. 

 Columella bearing two horizontal lamellae, the lower one some- 

 what more prominent. The lamellae are rather deeply placed 

 in the adult shell, but continue as low cords to the edge. In 

 the neanic stage they are unequal and not immersed. Length 

 2.5, diam. 1.3 mm. 



Molokai: Western ravine of Kamalo (Cooke & Pilsbry). 

 Type no. 112532 A. N. S. P., cotype in B. P. B. Mus. 



The base is abrupt, as in the T. perkinsi group. It is de- 

 cidedly narrower than T. thaanumi and T. idee. 



Group of T. cyphostyla. 



Tornatellides with elongate-conic spire and rather flat 

 whorls. The base tapers. The parietal lamella remains of 

 about the same height in adult and immature specimens, but 



