128 Art - 6.— M. Yokoyama: 



high and 10 millim deep, shows this character in a marked degree, 

 a character, which is also seen in some of our recent specimens. 

 The above valve has about thirty-three ribs besides those found 

 in the posterior area. 



Fossil occurrence: — Miyata Zone (Kami-Miyata, Shimo-Miya- 

 ta and Okine Nagai); Yokosuka Zone (Otsu); Upper Musashino 

 of Musashi, Kazusa and Shimosa. 



Living: — Northern to Western Japan; Behring Sea; British 

 Columbia ; California. 



159. Cardium muticum, Reeve. 

 Pl. IX. Fig. 11. 



Cardium muticum. Reeve, Conch. Icon., Cardium, pl. VI, fig. 32. Lischke, Jap. Meeres- 

 conch., I, p. 144. Brauns, Geol. Env. Tokio, p. 42. Tokunaga, Foss. Envir. Tokyo, p. 50, pl. 

 Ill, fig. 10. Dunkeb, Ind. Moll., p. 212. Pilsbry, Cat. Mar. Moll. Jap., p. 131. 



Cardium pajjyracetim. Römer in Syst. Conch. Cab., Mart. u. Chenin., vol. X, pt. 2, p. 78, 

 pl. in, fig. 4, pL.XII, figs. 19, 20. 



Cardium japonicum. Dunkeb, Moll. Jap., p. 28, pl. Ill, fig. 16. 



The shell is large, but very thin and fragile, suborbicular and 

 subequilateral, ornamented with numerous radiating riblets which 

 are flat and hardly elevated above the surface of the shell except 

 at the sides where they are more or less ridge-like. Their 

 number is over forty, each subdivided into two by a tine impress- 

 ed punctuated line. Beaks tumid. Our largest example measures 

 about 75 millim. in height, a little over it in length, and 29 millim. 

 in depth (right valve). Rare. 



Fossil occurrence: — Miyata Zone (Kami-Miyata and Nagai); 

 Yokosuka Zone (Yokosuka); Naganuma Zone (Naganuma); Upper 

 Musashino of Musashi and Shimosa. 



Living: — Northern, Central and Western Japan; Philippines; 

 East Indies. 



160. Cardium modestum, A. Adams et Reeve. 

 Pl. IX. Figs. 12, 13. 



Cardium vuulestum. Adams and Reeve, Voy. Samarang, Zool., p. 77. pl. XXII, fig. 6. 

 Dünker. Index Moll., p. 211. Pilsbry, Cat, Mar. Moll. Jap., p. 131. 



