LEPTACHATINA, S.-G. THAANUMIA. 83 



encircled by very minute, close, raised, spiral lines ; the suture 

 of the embryonic whorls is rather wide and deep and these 

 whorls are somewhat flattened and very slightly shouldered 

 above. Type L. omphalodes. 



Thaanumia can hardly be ranked as a genus, since except 

 for the minutely striate embryonic whorls, all the species 

 could undoubtedly be placed in Leptachatina. There are at 

 present eight species known. 



L. (Thaanumia) omphalodes Ancey, Oahu. 



L. (Thaanumia) optabilis n. sp., Oahu. 



L. (Thaanumia) morbida n. sp., Molokai. 



L. (Thaanumia) thaanumi n. sp., Molokai. 



L. (Thaanumia) henshawi Sykes, Hawaii. 



L. (Thaanumia) perforata n. sp., Kauai. 



L. (Thaanumia) dulcis n. sp., East Maui. 



All the species are from rather open and dry localities and 

 are not found in the deep woods. The characters of the em- 

 bryonic whorls are not easily seen, and in most cases are 

 only made out under a compound microscope. They are best 

 seen in rather young fresh specimens. 



107. L. OMPHALODES (Ancey). PI. 13, fig. 11. 



' The shell is openly umbilicate, ovately conic, glossy, with 

 a silky luster, acutely and irregularly longitudinally costu- 

 late with somewhat lamellate, slightly flexuous costas, dark 

 reddish corneous, pale purple at the lip. Spire regularly 

 conic, rectilinear in outline, subobtuse at the apex. Whorls 

 6, convex, regularly increasing, separated by an impressed 

 suture, the embryonic very minutely spirally sculptured, the 

 rest costulate, irregularly striatulate in the interstices, the 

 last at first subangulate, ovate, dilated, at the end minutely 

 and shortly ascending, angulate and compressed about the 

 umbilicus. Aperture perpendicular, receding at the base, ir- 

 regularly oval, contracted at both ends. Columella perpen- 

 dicularly descending, long, joined to the base with an ob- 

 tuse angle, at its base lightly twisted-plicate within. Lip 

 slightly expanded on all sides, expanded at the columella 

 more, with the margins not contracted. Length 6.3, diam. 3.5, 

 length of ap. 2.6 mm." (Ancey.) 



