TORN ATELL ARIA. 261 



7. T. TROCHOIDES (Sykes). PL 54, figs. 13-17; pi. 55, fig. 9. 



Shell deeply perforate, corneous, pyramidal, pellucid, nearly 

 smooth. Spire conoidal, the apex rather acute. Whorls 

 7-7!/2, regularly and slowly increasing, flattened, the last sub- 

 carinate at the periphery, suture impressed. Aperture 

 quadrate-ovate, angular above, bearing a strong, conspicuous 

 parietal lamella. Columella brown, thickened, provided with 

 two plica?. Length 4, diam. 2 mm. (Sykes). 



Lanai (Perkins, Thaanum, Spalding), Molokai (Thaanum, 

 Cooke), Hawaii: Waimea (Thaanum), fossil (Henshaw). 



Tornatellina trochoides SYKES, Fauna Hawaiiensis, ii, Moll., 

 p. 383, pi. 11, f. 31 (1900). 



"Closely related, apparently, to T. umbilicata Ancey, but 

 differs from it in the relative proportions of height and 

 breadth " (Sykes). 



It also differs by its less polished surface, smaller parietal 

 lamella and flatter whorls. 



T. trochoides and T. cincta are very intimately connected. 

 In the former the parietal lamella is weaker, the base shorter, 

 the umbilicus is slightly larger and the whorls more closely 

 coiled. It is by no means an easy matter to determine 

 Molokaian Tornatellarise. 



T. trochoides was described from a shell not absolutely 

 mature. The original figure is copied on pi. 55, fig. 9. 



A cotype, received from Mr. Sykes, pi. 54, fig. 16, has 7 

 whorls and measures, length 3.7, diam. 1.95, axis of aperture 

 1.4 mm. None of the cotypes received by the Bishop Museum 

 were wholly mature specimens, and in all of them the lower 

 columellar fold is slightly stronger than the upper. The 

 parietal lamella is minutely serrate along its edge ; the suture 

 is indistinctly margined ; and there are about ten low distinct 

 spiral striae on the embryonic whorls. The umbilicus is about 

 % of the total diameter of the shell. 



A lengthened form from Lanai, pi. 54, figs. 13, 14, meas- 

 ures length 5, diam. 2.5 long, axis of aperture 1.6 mm., with 

 9!/3 whorls. 



This species is widely distributed over the eastern half 



