1908-] NATURAL SCIENCES OF PHILA|)ELPHIA. 573 



several tubercular plicae on a distinct, curved ridge (fig. 6b), but are 

 larger: 



Length 15.0, diam. 3.5 mm.; whorls 9J. 

 12.3, " 3.0 " " 9i. 



3. Those from Irazuyama, Tosa (pi. 31, fig. 20), have a well developed 

 arcuate lunella between the upper and lower palatal plicae, but hardly- 

 joined to either (fig. 6c), specimens measure: 



Length 13.8, diam. 3 mm. ; whorls lOJ. 

 14.0, " 3 " " 10. 



4. A lot from Nametoko, lyo (pi. 31, figs. 14, 15), has a similar 

 curved lunella, and consists of specimens of two sizes, obviously from 

 two diverse stations. The larger shells are more or less worn, the 

 cuticle mainly lost, and measure 11.8 to 13.2 mm. long. The smaller 

 shells are glossy with the cuticle perfect, the lip is narrower, and the 

 subcolumellar lamella is not so long inside as the spiral. They measure : 



Length 9.4, diam. 2.2 mm. ; whorls 8f . 

 8.9, " 2.1 " " gi 



5. At Kotsuzan, Awa, the curved lunella is also perfect, as in (3) 

 and (4), The lip is better developed than in the smaller specimens 

 from Nametoko, lyo. Specimens measure: 



Length 10, diam. 2.3 mm. ; whorls 9^. 

 9, " 2.0 " " si 



These lots show that multifarious differentiation with consequent 

 formation of local races is in progress; but in the present condition 

 of our knowledge it would probably be inexpedient to recognize these 

 races by name. 



Clausilia pigra Pils. 



Proc. A. N. S. Phila., 1902, p. 368 (Kashima, Harima). 

 Specimens received from Nagami, Iwami and Yakuenji, Izumo, 

 differ slightly from the types. The aperture is built forward a little 

 less, and the lunella differs somewhat, being shaped more as in the 

 group of C. platyauchen, there being a ver}^ short lower palatal plica, 

 and the upper palatal plica is represented only by an inward bend 

 of the lunella, whereas in the types of pigra the upper plica stands 

 almost free of the lunella, and the whole structure is somewhat J- 

 shaped (rather than I-shaped, as originally described). 



Clausilia ikiensis tsushimana n. subsp. PI. XXXI, figs. 8, 9, 10. 



Shell somewhat larger and more robust than C. ikiensis, the subcol- 

 umellar lamella wholly immersed ; outer end of the lower palatal plica 

 joining the lunella. 

 37 



