Fossils from the Upper Musashino of Kazusa and Shimosa. Q\ 



large, which is generally the case with the whorl preceding the 

 penultimate. The subsutural cliestnut band found in the living 

 specimens is often preserved also in the fossil ones. Rather rare. 



Fossil occurrence. — Otake, Tega. Tabata (according to Toku- 

 naga). 



Living. — Central Japan. 



Family Skeneidae. 



Genus SK.E1VEA, Fleming. 

 10.>, Skettea »lippotiiefi, Yokoyama. 



PI. IV. Fio;. 7. 



Skenea nipponica. Yokoyama, Foss. Miura Peuin., p. 75, pi. Y. fig. 1. 



Two specimens, one of which is somewhat larger than that 

 described from the Lower Musashino, being 2.2 millim. in diameter. 



Fossil occurrence. — Shisui, Tega. Lower Musashino of 

 Yokosuka. 



Living. — Central Japan. 



lot». Sh-enen planorhoUles, Yokoyama. 

 PI. IV. Fig. 8. 



Shell small, thin, almost discoidal, Ijroadly umbilicated, 

 Whorls foui- and a half, rapidly growing, smooth, convex, separated 

 by deep sutures. Periphery roundly angulate. Base somewhat 

 convex. Umbilical margin angulate. Llmbihcal wall nearly ver- 

 tical. Aperture roundly triangular, one of the angles being in the 

 middle portion of the outer lip at the extreme end of the periphery. 

 A single specimen which is 2.5 millim. in height and 4,5 millim. 

 in diameter. 



This species is closely akin to Skenea planorbis Fabr. (Tryon, 

 Man. Conch., IX, pi. 60, fig. 100) of northern seas from which it 

 is distinguished b}^ its angulate periphery. 



The living specimens of this shell obtained in the Sea of Saga- 

 mi (Central Japan) are milk-white and translucent, and ornamented 

 with very tine spiral striae which are almost obliterated in the 

 fossil. 



