1904.] NATURAL SCIENCES OF PHILADELPHIA. 619 



Alt. 6, diam. 7.5 mm. 



Alt. 5.5, diam. 7 mm. 



Miyakojima, Riukiii. Typos No. 87,633, A. N. S. P.. from Xo. 1,296 

 of Mr. Hirase's collection. 



This species has a more elevated spire than the related C. minutus 

 of Formosa. 

 Cyathopoma iota n. sp. 



Shell minute, umbilicate, conic, thin, yellowish corneous, subtrans- 

 lucent. Surface glossy, nearly smooth. Whorls 3^, very convex, 

 tubular, parted by a deep suture, the last whorl at the aperture barely 

 in contact with the preceding. Aperture slightly oblique, circular, 

 the peristome thin and simple. The operculum lodges a short distance 

 within, is externally somewhat concave, cream-colored, concentrically 

 delicately striate, with a large somewh^^t sunken glossy translucent 

 central spot. 



Alt. 1, diam. 1.3 mm. 



Kumejima, Riukiu. Types No. 87,698, A. N. S. P., from No. 1,292 

 of Mr. Hirase's collection. 



This species is intermediate in contour between the Japanese C. 

 micron Pils. and C. innocens Sykes of Ceylon. It is much more ele- 

 vated than the former species. This species and Cyclotus micron belong 

 evidently to the subgenus Jerdonia of the genus CyatJiopoma, the oper- 

 culum being discoidal and somewhat biconcave, as in Cyclotus. Both 

 Cyathopoma and Jerdonia are Indian groups, not hitherto reported 

 from China or from any part of the Japanese Empire. 



DIPLOMMATINID^. 



The Diplommatinas of Japan and the Riukiu Islands are very closely 

 related to those of China. Besides Adelopoma,^ two subgenera or 

 sections of Diplommatina are represented. 



I. — Constriction at the beginning of the last whorl, in front, or on the 

 latter part of the penultimate whorl on the right side ; a palatal 

 plica and a parietal or "spiral" lamella developed in front of 

 the constriction, to which the columellar lamella also extends. 



Section Sinica Mlldff. 



II. — Constriction in the first part of the penultimate whorl, on the 



front or left side; the columellar lamella therefore nearly two 



whorls long; a palatal plica but no parietal lamella developed. 



Section Angigaster, type D. vespa P. and H. 



Sinica- includes all of the known Japanese and Riukiuan species 



1 Nautilus, XVII, p. 59. 



2 Vide Jahrb. D. Malak. Ges., XII, 1885, p. 369. The type of Sinica is Diploma 

 matina sculptilis MUdff., from the Chinese province Guang-dung. 



