l'.)(»7.] NATURAL SCIENCES OF PHILADELPHIA. 503 



'l\\v two s[)e('ic.s ul" this <;i-()U|) liithciin known were referred to 

 Ilemizaptyx as a second division {Proc. A. N . S. Phila., 1904, p. 825); 

 l)ut the discovery of more species with the same type of clausilium 

 makes it expedient to recognize the group by name. It is closely 

 related to Ilcniizaptyx in shell features, but dilTers in the peculiar 

 swell and callus along the outside of the clausilium near its palatal 

 l^order. 



The species now known are as follows : 



1. — Clausilium rather long, acuminate at the apex, which is a little 



hooked backward. 



a. — Upper palatal plica interrupted, a short portion being situated 



at the top of the lunella and a long one in the back of the 



last whorl, visible in the mouth. Formosa, C. diacoptyx. 



a*. — Upper palatal plica very long, extending nearly to the lip. 



Clausilium unknown. Formosa, . . . C uraniscoptyx. 



a-. — Upp(n- palatal plica short; shell striate. 



h. — Shell dark reddish-brown, glossy, and rather thin, 10 to 11 

 mm. long, 2 to 2.3 wide, with 1% whorls; sides of the 

 clausilium strongly reflexed. Tokunoshima, 



C. hyperaptyx. 

 ¥. — Shell pale chestnut or browmish corneous, rather thin, 11 to 

 13 mm. long, 2.7 wdde, with 9 to 10^ whorls; clausilium 

 distinctly hooked at the apex. Oshima, C. oxypomatica. 

 h-. — Shell browm or yellowish-brown, quite solid when adult, 12 

 to 15 mm. long, 3 to 3.6 wide, with 9 to 10 whorls. Clausi- 

 lium distinctly hooked at the apex. Oshima, C. munus. 

 1 1 . — Clausilium short, very wide distally, w'here it is broadly rounded 

 and recurved at the edge. Upper palatal plica very long, 

 approaching the aperture. Keraina-jima, Ryukyu, 



C. longiplicata. 

 CUusilia hyperaptyx ViU. 



Proc. A. N. S. Piiila., 1904, p. 827. 



The clausilium (PI. XXXII, fig. 10), seen from the palatal side, is 

 licre figured, to show the imusual wddth of the reflexed palatal margin. 

 The terminal hook is much less developed than in C. oxypomatica 

 [hyperaptyx, with no fold al)Ove). 



Clausilia munus Pils. 



Proc. A. N. S. Pliila., 1901, p. vn. 



The clausilium is here figured (PI. XXXIT, figs. 11, 12) from the 

 type specimen. It is conspicuously angular at the apex, which is 

 decidedly thickened, and in profile view is seen to be hooked back- 

 ward. The columellar margin is regularly arcuate, bordered by a 

 thickened rim. The palatal margin is rather strongly convex in the 

 middle, and above the middle it is very iiiucli thickened outside, as 



