1904.] NATURAL SCIENCES OF PHILADELPHIA. 831 



whorl is decidedly less striate. It is also paler and somewhat more 

 transparent. 



Length 10 to 10.5, diam. 2.4 mm. 



Yoronjima, Osumi. Types No. 88;767, A. N. S. P., from No. 1,253a 

 of Mr. Hirase's collection. 



Clausilia yaeyamensis n. sp. PI. LVI, figs. 80, 81, 82, 83, 84. 



Shell cylindric below, regularly tapering from the penultimate 

 whorl to the apex; dark chestnut, paler near the apex. Surface glossy, 

 evenly, -finely and sharply striate, the back of the last whorl a little more 

 irregularly so. Whorls 8^, the earlier ones quite convex, the later 

 much less so. Aperture piriform, the peristome expanded, whitish. 

 Superior lamella rather high, compressed, weakly continuous with the 

 spiral lamella, which penetrates nearly to the middle of the ventral 

 side. Inferior lamella deeply receding, nearly straight and obliquely 

 ascending within, shorter than the spiral lamella. Subcolumellar 

 lamella emerging. A parallel lamella and fulcrum present. Principal 

 plica about one-half a whorl long, dorsal and lateral, visible in the 

 aperture. Upper palatal plica very short, connected with the straight 

 lunella, which bends inward at its lower end. There are two sutural 

 plicae. 



Length 11, diam. 2.3 mm. 



Length 10.5, diam. 2.3 mm. 



Clausilium (PI. LVI, figs. 80, 81, 82) wider above than below, 

 obtusely rounded distally, abruptly excised at the filament. 



Yaeyama, Ryukyu. Types No. 80,963 and 87,561, A. N. S. P., from 

 No. 4576 of Mr. Hirase's collection. 



This species is related to C. hyperoptyx, from which it differs in the 

 even striation and very short upper palatal plica, and the weakly 

 continuous superior and spiral lamellae. The clausilium closely resem- 

 bles that of C. hyperoptyx. I reported this species under the name 

 hyperoptyx in these Proceedings for 1901, p. 651, not having at that 

 time opened the specimens. C. hyperoptyx has not been found on 

 Yaeyama, and probably does not occur in the southwestern group of 

 islands. 



Section METAZAPTYX nov. 



Similar to Zaptyx, except th^t the inferior (lamella ascends spirally 

 within and in the mouth is visible as a fold approaching the superior 

 lamella; the base of the shell is somewhat sack-like. The clausilium 

 is broad, strongly curved distally, shorter than thatjof Zaptyx, and 

 rounded at the apex. 



