1901.] NATURAL SCIENCES OF PHILADELPHIA. 405 



REALIID^E. 

 Omphalotropis japonicus n. sp. 



Shell narrowly umbilicate, acutely ovate-conic, rather thin, 

 yellowish brown; surface glossy and smooth. Spire straightly 

 conic, the apex rather acute. Whorls 6, convex, the last with a 

 stroiig basal keel around the umbilicus. Aperture slightly 

 oblique, ovate, the outer and basal margins of the peristome a 

 trifle expanded, columellar margin reflexed. Length 5.3, diam- 

 eter 3.5, length of aperture 2.5 mm. 



Kashiwashima, Tosa, Shikoku Island (Mr. Y. Hirase, No. 588). 



This is, I believe, the first Omphalotropis found in Japan. 



AMNICOLIDJB. 

 Bithynia striatula var. japonica nov. 



Shell pale amber tinted or corneous, glossy, similar to B. striatula 

 of China, but differing in sculpture, the spiral ridges being much 

 stronger; 3 or 4 large and irregularly spaced ones above the peri- 

 phery, those on the base smaller and closer. Alt. 10 (specimens 

 with the early whorls lost by erosion), diam. 6.5 mm.; longest 

 axis of aperture 5 mm. 



Manabe, Hidachi (type locality), and Osaka (Mr. Y. Hirase). 



Types No. 80,683 Coll: A. N. 8., from No. 152 of Mr. Hirase's 

 collection. 



Specimens from Osaka have less strong sculpture than those from 

 the province Hidachi, though it is still stronger than in any Chinese 

 specimens of B. striatula in the series before me. The peristome 

 is rather less expanded, too, though well thickened in adults, and 

 either black (Manabe) or pale (Osaka). B. striatula has already 

 been reported from Japan by Prof, von Martens, 16 who in 1660 

 found it at Yokohama, on the muddy bank of the small river, at 

 the first bridge, in quite fresh water. I suppose it was this strongly 

 sculptured form which he found. The Vega Expedition collected 

 shells identified by Westerlund as B. striatula at Jokogava (near 

 Tokyo), and at Lake Biwa ( Vega Exp., IV, p. 182). In China 

 the species is widely diffused, from the Yangtse to the Amur drain- 

 ages; and Pere Heude 17 has split it into some four species. Of 



1 6 Sitzungtber. naturf. Freunde zu Berlin, 1877, p. 114. B. striatula 

 was described from Chusan, as Paludina (Bithinia') striatula Bens.,Journ. 

 Asiat. Soc. Beng., XXIV, 1885, p. 131. Schmacker found it at Shanghai. 



17 Memoires concernant I' Hist. Nat. de I' Empire Ckinois, pp. 171, 172. 



