The shell is comparatively large, though thin. It is trian- 

 gular, compressed, rounded in front and bluntly angulate behind. 

 The height is about three-fourths of the length. Surface smooth. 

 Growth-lines distinct. 



The examples are all left valves. The largest measures 58.7 

 millim. in length and 43.8 millim. in height. 



Fossil occurrence in Japan. — Otake (rather rare). Tega. 



Fossil occurrence in America. — Pliocene and Pleistocene of 

 San Pedro, California. 



Living. — Central and Western Japan. California (Bodega Bay 

 to San Diego). 



Family Veneridae, 



Genus DOSINIA, Scopoli. 

 225. Dosinia froseheli, Lischke. 



Dosinia troscheli. Lischke, Jap. Meerescouch., Ill, p. 89, pi. VIII, figs. 1-3. Dunker, 

 Ind. Moll., p. 203. Yokoyama, Foss. Miura Penin., p. 119, pi. VIII, figs. 5,6. 



Dosinia exoleta. Brauns, Geol. Env. Tokio, p. 41, pi. VI, fig. 22. Tokunaga, Foss. 

 Env. Tokyo, p. 47. 



This shell so scarce in the Lower Musashino is of a wide 

 distribution in the Upper. That Lischke' s species is distinct from 

 its European ally, Dosinia exoleta L. , was explained in my work 

 above cited. 



, Fossil occurrence. — Otake, Shisui, Kamenari, Kioroshi, Tega, 

 Shito. Oji (quite numerous), Tabata, Dôkwanyama and Shina- 

 gawa in Musashi. Lower Musashino of Miyata and Naganuma. 



Living. — Central and Western Japan. . 



22<5. Dosinia bilunulafa, Gray. 

 Pi. X. Fjgs. 12, 13. 



Dosinia bilunidata. Gray, Analyst. Quart. .Jour., 1838, pars 24, p. 309. Reeve, 

 Conch. Icon., Dosinia, sp. 22. Römer, Monogr. Dosinia in Nov. Conch., p. 83, 

 pi. XVI, fig. 1. Lischke, Jap. Meeresconch., II, p. 172, III, p. 90. Dunker, lud. 

 Moll., p. 203. Pilsbry, Cat., p. 126. 



