1908.] NATURAL SCIENCES OF PHILADELPHIA. 571 



Inferior lamella forming a moderately prominent fold on the columella, 

 straightened and obliquely ascending in the back, and as long within 

 as the superior lamella. Subcolumellar lamella barely emerging, 

 not extending upon the lip. Principal plica about a half whorl long. 

 Palatal plicae 6, the lower five nearly equal, lateral, showing as a 

 whitish streak outside (fig. 5). 



Length 36.2, diam. 6.0 mm.; length of aperture 7.5 mm. 

 31.0, " 5.8 " " " 7 " 



Clausilium narrow with nearly parallel sides, the lower end rounded 

 and somewhat thickened. 



Taiwan (Formosa), at Taito (or Hinan). Types No. 94756 A. N. S. 

 P. from No. 1492 of Mr. Hirase's collection. 



This species has the dark color of C. swinhoei, and agrees with that in 

 the general structure of the aperture and internal plicae, but it differs 

 from that species by its long, narrow shape, greater number of whorls, 

 and the much more obsolete striation, that of C. swinhoei being com- 

 paratively close, fine and sharp, and not interrupted into long granules, 

 as it is in C. taiwanica. 



Section HEMIPH^DUSA Boettger. 



The type of this group is Clausilia pluviatilis Bens, of China, a 

 form closely related to species of the Japanese group of C. platyauchen. 

 An arrangement of the Japanese species was given in these Proceedings 

 for 1901, p. 623, and pp. 648-651. Subsequent studies have added 

 many species and caused the removal of some originally included in 

 HemiphcBclusa to form new sections — Nesiophcedusa, Luchuphcedusa 

 and Zaptyx. Moreover, it appears that the species with several palatal 

 plicae are not separable from those with an I-shaped lunella (cf. C. 

 tosana, etc.). A new classification of the species is therefore in order: 



Groups of Japanese Hemiphcedusce. 



a. — Lunella well developed, curving inward above, and below united 

 to the middle of a straight or arched lower palatal phca. Clau- 

 silium scarcely or not excised at the palatal side of the filament, 



Group of C. platyauchen. 



a*. — Clausilium deeply excised at the palatal side of the filament. A 



lower palatal plica present, or represented by an inward curve 



of the lower end of the lunella. 



h. — Lunella well developed, J-shaped, the lower palatal plica 



represented only by the inward curve of its lower end. 



Apical end of clausilium simple. 



c. — Principal plica very small or wanting; no upper palatal 



plica .Group of C. hyperolia. 



