154 Art. 1. — M. Yokohama: 



Two right valves and one left. 



The shell is somewhat obliquely ovate, higher than long^ 

 moderately convex and ornamented with straight, rounded, 

 radiating ribs separated from one another by deep narrow grooves 

 and numbering a little over forty. The ribs found near the extreme 

 end of the flattened posterior surface are accompanied by fine 

 riblets which are roughly crenate, or even sj^iny, toward their 

 lower ends. 



The larger of the two right valves is 63. omillim. in height, 

 59.7 millim. in length and 20.5 millim. in depth, while the 

 smaller has the posterior and postero-dorsal margins more arched 

 and is comparatively highei' and less deep, being 20.8 millim. in 

 height 20.6 millim. in length and d.G millim. in depth. The 

 left valve is 37 millim. in height, 36 millim. in length and 11.5 

 millim. in depth. 



Fossil occurrence. — Kamenari, Tega. 



Living. — Central and Western Japan. 



343. Carditttn cttliforniettse, Deshayes. 



Cardium californimse. Deshayes, Revue Zool., p. 1. Soc. Cuvierienne, p. 360. Mid- 

 dendorff, Sib. Reise, Meeresmollusken, p. 218, pi. XIX, figs. 6-11. Mai. Ross., Ill, 

 p. 40, pi. XV, figs. 23-25. Scbreuck, Moll, Amurl. u. d. uordjap, Meeres, p. 514. 

 Lischke, Jap. Meerescouch., I, p. 144, III, p. 125. Brauns, Geol. Env. Tokio, p. 

 42. Yokoyama, Foss. Miura Penin., p. 127, pi, IX, fig. 10. 



The specimens, though numerous, are mostl}^ small. But 

 there is a broken right valve from Shisui measuring 40 millim. in 

 height. 



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

 (frequent). Oji and Shinagawa. Lower Musashino of Miyata and 

 Yokosuka. 



Living. — Northern, Central and Western Japan. Behring 

 Sea. British Columbia. California. 



244. Cardium tnufietitu, Reeve. 



PI. XII. Fig. 7. 



Canliam wuticam. Reeve, Conch. Icon., Cardium, pi. VI, fig. 32. Lischke, Jap. 



