1901.J NATURAL SCIENCES OF PHILADELPHIA. 631 



from the mouth, except for a slender continuation across the lip 

 parallel with the subcolumellar lamella in most specimens, but 

 often wanting. It ascends rather straightly but obliquely inside, 

 and continues inward as far as the spiral lamella. The principal 

 plica is almost a whorl long, approaching the aperture, and con- 

 tinued within past the ventral side. The lunella is latero-ventral 

 or almost ventral, oblique, almost straight, but curved a trifle 

 inward above, and connected with a strong lower palatal plica very 

 near its inner end. 



The clausilium (PI. XXXVI, figs. 20, 21) is parallel -sided, 

 very obliquely cut off and thickened on the columellar side of the 

 apex. It is deeply emarginate or excised on the columellar side 

 of the filament. 



I have received specimens from the following localities: Nippon 

 Kobe, Setsu; Takaya, Bitchu; Toyonishikami, Nagato. Sen- 

 zan, Awaji. Shikoku: Ushirogawa and Okinoshima, Tosa. 

 Kiushiu: Fukuregi and Yatsushiro, Higo. 



The distribution of 0. bilabrata includes southwestern Nippon, 

 Awaji and Shikoku Islands, Kiushiu and the Iki Islands; the 

 latter locality on the authority of Dr. O. von Mollendorff, who 

 records specimens collected by Fruhstorfer. 



While there is some variation from place to place, 1 do not see 

 grounds for the definition of any races or subspecies, except the 

 variety defined by Boettger, which I have not seen. The degree 

 of plication of the right margin of the peristome is subject to wide 

 individual variation in C. bilabrata, C. Oscariana and C. suru- 

 gensis. 



Specimens from Kobe are pale colored, retain 7^-9 whorls, and 

 either have the right margin plain, except for the emerging inferior 

 and subcolumellar lamellae (fig. 17), or many-folded (fig. 19). 

 They measure between, alt. 22.5, diam. 5.5 mm., whorls 9, and 

 alt. 20, diam. 4.8 mm., whorls 8. At Takaya, Bitchu, the shells 

 are larger, and vary from a single emerging lamella, the subcol- 

 umellar. to three or four folds. Alt. 25, diam. 5.8 mm., whorls 

 8-J; alt. 21, diam. 6 mm., whorls 7-J-. They are corroded, and 

 more or less clothed with green algae on the back (figs. 23, 24). 



Toyonishikami, Nagato. Dark reddish-brown, with the lunella 

 decidedly fofero-ventral, and the principal plica shorter; lip with 

 numerous folds. Alt. 23.5, diam. 5.6 mm., whorls 9J. 



