572 



PROCEEDINGS OF THE ACADEMY OF 



[Dec, 



c^ — Principal plica well developed ; a short upper palatal plica, 

 or the lunella bent inward in its place, 



Group of C. awajiensis. 



b^. — Lunella, etc., as in the group of C. awajiensis, but there is a 



lower palatal nodule at its lower end; clausilium in apical 



view appearing deeply notched, . Group of C. aidacopoma. 



6^ — Lunella either I-shaped, or replaced by a series of palatal 



plicse, Group of C. validiuscula. 



fr. — A short, straight, or nodule-like, or rudimentary lunella, not 

 curving inward at the lower end, below one or two palatal 

 plicse; no lower palatal plica. Clausilium not excised at the 

 palatal side of the filament, . . . Group of C. sublunellata. 



Clausilia tosana Pils. PI. XXXI, figs. 14-20. 



Proc. A. N. S Phila., 1900, p. 680, pi. 25, figs. 22-25, 4L 

 This species is now before us from five localities, all on Shikoku 

 Island. It shows remarkable variation. All have the last whorl 



Fig. 6. — Clausilia tosana. a, typical form from Ushirohawa, Tosa; b, variety 

 from Shimohanyama, Tosa; c, variety from Irazuyama, Tosa. 



built forward, Cylindrella-like, with a furrow outside above the 

 principal plica, and the subcolumellar lamella is always very deeply 

 immersed. Internally the spiral and subcolumellar lamellse are 

 usually of equal length, reaching inward to the middle of the ventral 

 side, and the inferior lamella between them is shorter. 



1. The types from Ushirokawa, Tosa (pi. 31, figs. 16, 17), have 

 several palatal plicse standing upon a ridge (fig. 6a) and measure: 



Length 12.2, diam. 2.6 mm.; whorls 10^ 

 11.0, " 2.5 " " U. 



11.0. " 2.3 " " 9^. 



10.5, " 2.5 " 



2. A lot from Shimohanyama, Tosa (pi. 31, figs. 18, 19), also have 



