146 -^rt- 1- — M. Yokoyarua: 



Genus MERETRIX, Lamarck. 



229. Met'etriao nieretvioc, (Linné). 



P]. XL Fig. 4. 



MeretriiV meretnx. Pilsbry, Catalogue, p. 126. Eomer, in Malak. Blatter, p. 45, 



Monogr. Venus, p. 27, pi. 8, fig. 1. 

 Cytherea meretnx. Linné, Syst. Nat., Ed. 10, p. 686. Lischke, Jap. Meeresconcb, I, p. 



122, ir, p. 108. Dunker, Ind. Moll. p. 199. Pfeiffer in Syst. Conch. Cab., vol. 



XI, pt. 1, p. 15, 1)1. Ill, figs, 4-9. Brauns, Geol, En v. Tokio, p. 53. Tokunaga, 



Foss. Env. Tokyo, p. 47, pi. III, fig. 5. 

 Venus {Meretriiv) meretnx. Sclirenck, Moll. Amurl. u. d. nordjap. Meeres, p. 545. 



This well known tumid triangnlar shell, so common in the 

 seas around Japan, has already been described by Brauns and 

 Tokunaga from the fossil layers near Tokyo. 



The specimen figured is a large left valve about 84 millim. in 

 length, 68 millim. in height and 25 millim, in depth. It is markedly 

 triangular with the curvature of the ventral margin rather small. 



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

 Kioroshi, Tega (frequent). Shinagawa in Musashi. 



Living. — Northern, Central and Western Japan. Philippines. 

 Moluccas. Indian Ocean. 



230. Mcfretrix {Callista) chinensis, (Chemnitz). 

 PI. XI. Fig. 5. 



Meretrix {Callista) chinensis. Pilsbry, Catalogue, p. 127. Yokoyama, Foss. Miura 



Penin., p. 120, pi. VIII, figs. 9, 10. 

 Cytherea chinensis. Pfeiffer in Mart. Cliemn. Syst. Concli. Cab., XI, pt, 1, p. 31, X, 



fig. 2. Lischke, Jap. Meeresconcb., I, p. 122. Tokunaga, Foss. Env. Tokyo, p. 



46, pi. Ill, fig. 4. 

 Callista chinensis. Dunker, Ind. Moll., p. 200. 

 Venus chinensis. Chemnitz, Conch. Cab., XI, p. 227, pi. 202, fig. 1976. 



Specimens are quite frequent. The largest is from Shito, 

 measuring 120 millim. in length and 85 millim. in height. 



'Fossil occurrence. — Otake (common), Tega, Kamenari, Shisui, 

 Shito (rather frequent). Oji and Shinagawa in Musashi. Lower 

 Musashino of Naganuma. 



Living. — Northern, Central and Western Japan. China Sea. 

 Australia. 



