1905.] NATURAL SCIENCES OF PHILADELPHIA. 709 



Alt. 15, diam. 26.3 mm. 



Alt. 12.7, diam. 25 mm. 



Tokunoshima, Osumi. Types No. 87,501, A. N. S. Phila., from No. 

 1,211 of Mr. Hirase's collection. 



This species, while related to E. mackensii. is smaller and much more 

 delicate, almost to be called fragile. The cuticular processes are 

 shorter; the surface when rubbed is seen to be closely and distinctly 

 striate spirally, and the base is not so angular around the umbilicus. 

 It is a much thinner, weaker shell than E. vulgivaga. 



The Ganesella largillierti group consists of richly colored and beauti- 

 ful snails, confined, so far as we know, to the Oshima and Okinawa 

 groups — the central islands of the Ryukyu chain. The following forms 

 may be recognized: 



I. — Surface with extremely weak spiral striae or none, 



G. largillierti C'Phil." Pfr.). 

 II. — Spiral striation minute but distinct. 



a — Spire straightly pyramidal; altitude exceeding the diameter, 



G, adelina; Pils., Oshima. 

 a* — Spire obtuse; diam. exceeding the alt., 



G. sororcula Pils., and varieties. 

 b. — Spire conoidal; columella nearly vertical; diam. about 

 2 mm. greater than the alt., 



G. sororcula, typical; Kikai. 

 6^. — Spire lower; columella more sloping; 21 x 26 to 17 x 21 

 mm., G. s. tokunoshimana P. and H., Tokunoshima 

 and Oshima. 

 b^. — Still more depressed, columella oblique; size about 21 x 28 

 mm., G. s. okinoerabuensis P. and H., Okinoerabu- 

 shima. 

 b^. — Like typical sororcula, but with less conic spire and 

 nearly closed umbilicus, 



G. s. iheyaensis P. and H., Iheyajima. 



Ganesella sororcula okinoerabuensis n. subsp. 



Narrowly umbilicate, broad and low-conic, light yellow with a broad 

 purplish-brown band immediately above and another a short dis- 

 tance below the periphery. Spire bicolored, the lower half of the pe- 

 nultimate whorl purple-brown, the upper half yellow; on the next 

 earlier whorl purple replaces the yellow ; and the upper two whorls are 

 dark purple-brown. The surface is finely striate spirally. 



Alt. 22, diam. 28 to 28.5 mm.; whorls 5^. 



Okinoerabushima, Osumi. Types No. 89,996, A. N. S. Phila., from 

 No. 1,337 of Mr. Hirase's collection. 



