]^48 ■'^'■t 1- — ^- Yokoyama : 



Fossil occurrence. — Otake (numerous), Kioroslii, Kamenari' 

 (frequent), Tega. 



Living. — Northern, Central and Western Japan. South 

 Australia. 



Genus VENUS, Linné 

 232. Venus (Jftercenaria) sthnpsotti, Gould. 



PL XI. Pigs. 11, 12. 



Venus {Mercenaria) stimpsoni. Gould, Otia Concli., p. 169. Brauns, Geol. Euv. Tokio, 



p. 40, pi. V, fig. 21. Schreuck, Moll. Amuil, u. d, nordjap. Meeres, p. 604. 

 Venus stimpsoni. Tokunaga, Foss. Env. Tokyo, p. 46. 



Shell solid, rather compressed, ovatel}^ triangular, broader 

 than high, bluntl}^ angular behind, very inequilateral, the beaks 

 being near the anterior margin. Surface ornamented with thin, 

 erect, concentric lamellae. Lunula deep, well bounded, longly 

 cordate. Area very long, rather distinctly bounded, taking nearly 

 the wdiole length of the postero-dorsal slope of the shell. Of the 

 three strong main teeth, the middle one in the left valve is bifid, 

 while in the right the middle as well as the posterior are bifid. 

 Palhal sinus small, shallow, triangular. The inner margin of the 

 shell is finely crenulate, though Gould calls it simple. 



The largest specimen obtained is a left valve measuring 95' 

 millim. in length, 80 millim in height and 23 mihim. in depth. 



Fossil occurrence. — Otake (frequent), Shisui (do), Shito (do). 

 Oji in Musashi. 



Living. — Northern to Western Japan. 



233. VenUs Jetloensis, Lischke. 



Venus jedoensis. Lisclike, Jap. Meeresconcb., Ill, p. 84, pi. VII, figs. 1-9. Dunker, Ind. 

 Moll., p. 196. Pilsbry, Cat., p. 127. Yokoyama, Foss. Miura Penin., p. 120, pi. 

 YIII, figs. 9, 10. 



This shell fully described by Lischke is readily known by 

 its rather thick, tumid, transversely and shortly oval, inequilatei'al. 

 form with radiating ribs crossed by concentric lines of growth. 

 Lunula cordate bounded by distinct grooves. Inner margin 

 crenulate. Pallial sinus moderately deep, narrowing towards its. 



