188 PLEURODISCID.VE. 



rather irregularly striate. Whorls 4i/^, very convex, separated 

 by a very deep suture, the last rounded at the periphery and 

 beneath. Aperture oblique, rounded, about one-fourth of the 

 circumference excised at the parietal wall by the preceding 

 whorl; peristome simple and thin, the columellar margin a 

 little dilated. Umbilicus perspective, contained 3I/2 times in 

 the diameter. Alt. 1.3, diam. 2.8 mm. 



Japan: Suimura, Awa, Shikoku. Types no. 83884, A. N. 

 S. P. 



Pyramidula conica Pilsbry & Hirx\se, 1902, Nautilus XVI, 

 p. 77. 



This species is excessively similar to the common European 

 P. rupestris, and in separating it specifically I was somewhat 

 influenced by the enormous distance of its habitat from the 

 range of the European species. Lately, however, a form of 

 rupestris has been traced into high Asia, P. r. przevalskii 

 Lindh., in Eastern Turkestan, about Ion. 81 E. This is still 

 a long distance from Shikoku, in E. Ion. 134. It is probably 

 best to treat the insular Japanese form as distinct from the 

 European, pending a comparison of the anatomy. It differs 

 by the more tubular, less depressed last whorl and rounder 

 aperture. 



In this connection it may be well to notice some Chinese 

 snails described as Pyramidula. Pyramidula (Patula) peipi- 

 nensis Ping & Yen, 1932 (Bull. Fan Mem. Inst. Biol. Ill, No. 

 2, p. 25) is either a Hippeutis or a small northern form of the 

 common "Planorhis" umhilicalis Bens., which has a shell like 

 Hippeutis, but may be a toothless Segmentina. Pyramidula 

 (Patulastra) grahaui and P. (P.) gracilis Ping & Yen, 1933 

 (same Bulletin, vol. IV, No. 6, pp. 263-6), are Zonitidae. 



Pyramidula humilis (Hutt. & Bens.) . PI. 23, figs. 1, la, lb, 2. 



Shell small, convexly depressed, corneous, broadly and 

 deeply umbilicate; whorls 5, rounded, the last subangulate, 

 the penult slightly interrupts the circular aperture ; peristome 

 acute. Diam. 0.125 inch. {Benson). 



