260 TORN ATELL ARIA. 



umbilicus is conspicuously wider. It is less conic than T. 

 sharpi of Hawaii. Named for Mr. John F. G. Stokes, ethnol- 

 ogist of the Bishop Museum. 



6. T. UMBILICATA (Ancey). PI. 54, figs. 11, 12. 



Shell glossy (in the young state), openly and deeply um- 

 bilicate, the umbilicus minute, punctiform, rufous-corneous, 

 dextral, smooth, pellucid, thin, ovate-conic. Spire conoidal, 

 the apex a little obtuse, long. Whorls (in immaturity) 7%, 

 regularly and slowly increasing, the upper ones more convex, 

 lower scarcely convex, narrowly pellucid-margined; the last 

 whorl short, swollen. Aperture oblique, emarginate, angular 

 above, with a very strong, compressed, very prominent re- 

 volving parietal lamella. Columella acutely biplicate, the 

 upper fold stronger. Dimensions of the young specimens 

 described above, length 3.75, diam. 2.5, alt. apert. 1.33 mm. 

 (Ancey). 



West Maui: Lahaina (type loc.) (Baldwin), Maunahooma 

 (Cooke). Molokai: widely distributed over the eastern half 

 (Thaanum, Cooke & Pilsbry). Type no. 18451 Bishop Mus. 



Auriculella umbilicata ANCEY, Bull. Soc. Malac. France vi, 

 1889, p. 232. Tornatellina umbilicata ANCEY, Mem. Soc. 

 Zool. France v, p. 721. 



T. umbilicata is intermediate between T. trochoides Sykes 

 and T. newcombi Pfr. It is more closely related to the former 

 but differs in its glossier surface, more convex whorls, shorter 

 base and higher parietal lamella. From T. newcombi it differs, 

 mainly, by its smaller umbilicus and higher parietal lamella. 



Typical specimens from Maunahooma measure length 3.9- 

 4.25, diam. 2.25-2.5, axis of apert. 1.6 mm. Height of parietal 

 lamella 0.33-0.36 mm. The umbilicus is 1/10-1/14 of the total 

 diameter of the shell. The parietal lamella is minutely serrate 

 along its margin. The spiral strige on the embryonic whorls 

 are very low and indistinct. In immature specimens (fig. 12) 

 the upper columellar fold is slightly stronger than the lower. 



Mr. Ancey at first described this species as a young Auri- 

 culella, but subsequently he recognized that the shells were 

 nearly adult Tornatellinas. 



