1901.] NATURAL SCIENCES OP PHILADELPHIA. 467 



and a half wide. A chain of islets reaches northward to 'the 

 Sagami Sea; but I am disposed to believe that its molluscan fauna 

 has been derived chiefly from the islands south of Kiushiu by means 

 of drift, as it lies directly in the Kuro Shi wo, or " Black Current," 

 and Zaptyx, the group to which C. Haehijoensis belongs, is dis- 

 tinctly a southern group, unknown in Hondo Island. Small islets 

 at wide intervals are scattered down to the Bonin (Ogasawara) 

 group, but they rise from a submarine ridge in the sea bed between 

 1,000 and 2,000 fathoms depth. 



The two s])ecies of Clausilia here described and Clausllla 

 (Reinia) varlegata var. nesiotica Pils. are the first land shells 

 known from the island. 



, Section EUPH^^DUSA Bottger. 



Clausilia Tryoni n. sp. PI. XXV, figs. 1, 2, 3. 



Shell small, rimate, thin, fusiform, dark purplish brown, glossy. 

 finely striatulate, the last whorl more coarsely rib-striate. Whorls 

 8, rather convex, the apex obtuse, next three or four whorls 

 attenuated, the last whorl flattened on its last half. Aperture 

 piriform, the peristome rather thin, narrowly expanded and sub re- 

 flexed, continuous, adnate or very shortly free above, deeply emar- 

 ginate at the position of the superior lamella. Superior lamella 

 thin but high, continuous with the spiral lamella. Inferior lamella 

 rather small, weak below, though emerging nearly to the lip-edge, 

 rather abruptly becoming stronger and converging toward the 

 superior lamella within, strongly spiral. Suheolumellar lamella 

 emerging. Principal plica short, its lower end visible from the 

 aperture, deep within the throat, the other end extending past the 

 palatal plicae to a lateral position. Upper and lower palatal pliae 

 small, oblique and parallel, lateral in position, the lower one 

 smaller. There is no trace of a lunella. The inferior and spiral 

 lamellre are of equal length within, and reach to the middle of the 

 ventral side. 



The clausilium is broad, strongly curved, a little pointed or 

 tapering toward the apex, and very slightly thickened there. 



Length 11^, diam. 3 mm. 



Bachijo (Hachijo) Island, prov. Izu (Mr. Y. Hirase, No. 

 638). 



This pretty little Eapha;dasa was sent with Clausilia (^Zaptyx) 



