1902.] NATURAL SCIENCES OF PHILADELPHIA. 25 



NEW LAND MOLLUSCA FROM JAPAN AND THE BONIN ISLANDS. 

 BY HENRY A. PILSBRY. 



A monographic account of the non-marine mollusks of the Bonin 

 Islands (Ogasawara-jima) is now in preparation, in which all of the 

 species will be illustrated. As Mr. Nakada is still collecting in 

 the islands for Mr. Hirase, and will probably spend a month or two 

 more there, it has been thought desirable to publish brief notices of 

 his discoveries, reserving the consideration of the extrinsic relations 

 of the Ogasawaran fauna for the article to follow. 



Besides the material sent by Mr. Hirase, I am indebted to Mr. S. 

 Yoshiwara, of the College of Science, Imperial University, at 

 Tokyo, for valuable specimens and data which will be fully utilized 

 in the projected monograph. One of the most interesting of Mr. 

 Yoshiwara' s discoveries is the true locality of Mandarina ruschen- 

 bergeriana (Pils. ), which he found on the islet Minami, off the 

 southern end of Chichi jima. 



HELICINA Lam. 



This genus is represented in the Bonin Islands by several species 

 and varieties, all more or less related, and doubtless claiming a 

 common ancestor, though several of them are conspicuously diverse. 

 Those now known from Hahajima may be determined by the fol- 

 lowing key : 



a. Spire elevated, conic; lip simple, blunt, unexpanded. Whorls 



4^-. Alt. 4, diam. 5.2 mm., H. capsula n. sp. 



a 1 . Spire convex or merely somewhat conoidal; base convex; lip 



more or less expanded or thickened. 

 b. Periphery conspicuously carinate; lip expanded and 



thickened. 



c. Whorls 4; strongly striate spirally above. Alt. 3.2 

 or 3.3, diam. 5 mm., . H. ogasawarana n. sp. 

 c 1 . Much depressed and very acutely carinate; pale 

 yellowish-corneous ; whorls 4J. Alt. 2. 7 to 3, 

 diam. 5.8 to 6 mm., H. hirasei n. sp. 



6 1 . Periphery more or less angular, or rounded though com- 

 pressed. 



