524 PROCEEDINGS OF THE ACADEMY OF [AugUSt , 



II. — Superior lamella wauliug, or represented by a slight thicken- 

 ing of the peristome only. No lunella ; 2 palatal plicse. 

 a. — Aperture piriform, . . G^^oup of C. Jmngerfordiana. 

 b. — Aperture oval, hardly narrower above than below, 



Group of C. euholostoma. 



The groups are successively more aberrant in the ox'der given 

 above, this phylum having its acme in the section Reinia. 



Two species, G. subgibbera and G. expaiisilabris, described by 

 Boettger from Kein's collection, are not known to me by specimens, 

 and their exact localities in Japan are unknown. All of ihe other 

 species are represented in the collection of the Academy, and are 

 described and figured, in this paper and preceding ones of the series. 



Group of C. shanghcdensis. 

 Key to Species. 



I. — Superior lamella high; inferior lamella forming a co)ispicuous 

 convex fold in a front view of the aperture ; subcolumellar 

 lamella emerging; short upper and lower palatal plicse, 

 but no trace of a lunella. Shell glossy, dark purplish- 

 brown. 11.5 by 3 mm. Hachijo Island, Izu, . C. tryoni. 

 II. — Superior lamella moderately developed; inferior lamella 

 forming a low, convex fold in a front view, approaching 

 close to the superior ; shell rib-striate. 

 a. — Brown; length 13-14 mm., .... C. digonoptyx. 

 a'. — Greenish -corneous; palatal plicse shoit, lunella incon- 

 spicuous, almost wanting; length 10 mm., G. comes. 

 III. — Superior lamella small or reduced to a low cord; inferior 

 lamella showing in front as a low fold, not converging 

 strongly toward the superior lamella; shell dull brown- 

 ish, finely striate. 

 a. — Superior lamella small but distinct; spiral lamella high; 

 upper palatal plica long, connected in the middle with 

 a J-shaped lunella, which is w'eak in the middle, and 

 strengthened below into a nodule, .... G. tau. 

 a'. — Superior and spiral lamellre reduced to a low cord; palatal 

 plicse short. 

 b. — Length 13-lfi, diam. 3-3.5 mm. ; upper and lower 

 l)alatal plicse weakly connected by a low, imper- 

 fect lunella, visible as a whitish streak exter- 

 nally. Kyushu, G. subaeulus. 



b'. — Length 13.5, diam. 2.7 mm. ; small upper and lower 

 ^. palatal plicte, but no lunella. Yesso, G. rowlandi. 



