1IM)1.] NATURAL SCIENCES OF PHILADELPHIA. 623 



I must again express ray deep obligation for material to Mr. Y. 

 Hirase, of Kyoto, Japan. His tireless researches, critical eye for 

 detecting species, and exactness in recording localities are worthy 

 of high commendation. Without these qualities the new and 

 relatively exact literature of Japanese land mollusks would not 

 exist. 



Section HEMIPH^DUSA Boettger. 



The system of groups set forth by Dr. Boettger in the Clau- 

 silienstudlen, while sufficient at that time, is quite inadequate for 

 the classification of the great number of Chinese and Japanese 

 species now known. For Japanese species my studies lead me to 

 adopt the arrangement offered below. The clausilium in all the 

 groups is rounded or tapering at the end, and not thickened or 

 only slightly so. 



a. — Inferior lamella spirally ascending within, visible in a front 

 view, receding less deeply than in other Hemiphiedusoi ; shell 

 rather large ; superior lamella continuous with the spiral. 

 h. — Interlamellar space corrugated; lucella united to the mid- 

 dle of a lower palatal plica, contiguous to or united with 

 an upper pala'al plica near the middle (fig. 2). 

 Clausilium tapering below, recurved and spoutlike at 



the apex, Group of C. ptychochila. 



h\ — Interlamellar space smooth; luuella curving inward above, 

 uuited below to the middle of the lower palatal plica 

 (figs. 3, 4). Clausilium narrowly tongue-shaped. 



Group of C. platyauchen. 

 a\ — Inferior lamella receding, inconspicuous or not visible in a 

 front view. 

 b. — Several palatal plicie; no lunella (fig. 11), 



Group of C. validluseida. 

 6\ — A short or rudimentary lunella below one or two palatal 

 plicje; no lower palatal plica (figs. 9, 10), 



Group of C. suhlunellata. 

 h'\ — A lunella developed. 



c. — No palatal plicje; plica principalis subobsolete or 

 wanting; superior lamella separated from the 

 spiral lamella (fig. 5), . Group of C. hyperolia. 

 (•'.—Superior continuous with the spiral lamella; principal 

 plica well devel 'ped ; an upper palatal plica px'esent. 

 Clausilium curved, concave on the inner face. 

 d. — Lunella bow-shaped (fig. H) or J-shaped (fig. 7), 

 united to the upper palatal plica, curved in- 

 ward below; superior and spiral lamelkc united, 

 Group of C. awajien--<i-^. 



