596 PROCEEDINGS OF THE ACADEMY OF [DeC, 



total diameter of the shell. Wliorls 5f, slowly increasing, the last 

 much wider, rounded at the periphery. The suture is narrowly trans- 

 parent-margined. Umbilicus very small, its diameter contained about 

 20 times in that of the shell. Aperture lunate. 



Alt. 7.6, greater diam. 13.2, lesser 12 nmi. 



Sasuna, Tsushima. Types No. 95802 A. N. S. P., from No. 1549a 

 of Mr. Hirase's collection. Also found at Fusan, Korea. 



Fig. 2. — P. subrejecta. 



Compared with the Chinese P. rejeda, this species is less depressed 

 and has, viewed from above, a much wider spire and narrower last 

 whorl. The aperture is consequently higher and less dilated laterally. 

 The spiral sculpture is not quite so deeply engraved, and the umbilicus 

 is wider than in P. rejeda, though still very narrow. P. suhrejeda 

 is probably the shell A. Adams reported from Tsushima as Macro- 

 chlamys rejeda Pfr. 

 Petalochlamys serenua n. sp. 



The shell is depressed, very narrowly umbilicate, amber colored, 

 subtransparent, very fragile. The surface has dehcate, close micro- 

 scopic engraved spirals both above and below. Spire slightly convex; 

 whorls 4, but slightly convex, slowly increasing to the last, which is 

 much wider, rounded peripherally. The suture is narrowly trans- 

 parent-margined. Aperture lunate, columellar lip triangularly dilated 

 at the insertion, thin; columella vertical, 



Alt. 2.8, greater diam. 4.7, lesser 4 mm. 



Kaminoyama, Kunchan, Okinawa. Types No. 95809 A. N. S. P., 

 from No. 1441 of Mr. Hirase's collection. 



This small, very fragile shell is related to P. doenitzi (Reinh.), 

 but the last whorl is wider in a view from above, and is somewhat 

 more ample. 

 PetalocMamys perfragilis sakui subsp.n. 



The shell is more depressed than P. perfragilis and P. p. shiko- 

 kuensis, and is a little more openly umbilicate. Surface brilHantly 

 polished, almost smooth, but under a compound microscope very 



