Fossils froiü the Upper Musashino of Kaziisa and Shiuiosa. 2.31 



Althougli the shell is generally moderately thick, there are 

 •oecasioDally thin shelled specimens among the yomiger ones. 

 Fossil occui'rence. — 8hito (not rare), Kioroshi. 

 Living. — Western Japan. 



Genus RAETA, Gray. 

 lî)9. Raeta fjokohtttnensis, Pilsbry. 

 PI. VIII. Fig. 5, 6. 

 Baeta yokohamemis. Pilsbry, Catalogue, p. 119, pi. Ill, figs. 4, 5. 



A thin, fragile, white, swollen shell ovately triangular in 

 shape, compressed, bluntly pointed and a little .gaping behind, 

 with the surface concentrically corrugated. 



Fossil occurrence. — Otake (rather frequent), Tega (frequent). 

 Shisui, Kamenari. Oji in Musashi. 



Living. — Central Japan (Tokyo Ba^"). 



200. Raeta pellicula, (Deshayes) 



PI. IX. Fig. 6. 



Baeta pellicula. Pilsbry, Cat. Mar. Moll. Jap., p. 119. 



Mactra pellicula. Desbayes, Proc. Zool. Soc. Loud., 1854, p. 68. Pteeve, Concb, Icon., 

 Mactra, pi. XXI, fig. 124. 



An imperfect left valve swollen and rounded in front, some- 

 what flattened and truncate behind. The thin shell shows 

 concentric furrows on the surface. It is 23 (?) millim. long, 18.5 

 millim. high and 6 millim. deep. 



Fossil occurrence. — Otake. 



Living. — Japan (according to Reeve). 



201. Raeta elliittiea, Yokoyama. 

 PI. Vni. Fig. 7. 



Shell thin, fragile, transversely ovately elliptical, inflated, 

 somewhat flattened near the posterior end, wdth posterior side a 

 little shorter than anterior, rounded at both ends, though some- 



