126 Art - 6 - — M Yokoyama : 



Without going into the discussion of whether Tapes philip- 

 pinarum An. and Rve is not identical with Tapes decu&satus L. of 

 the Atlantic as maintained by some, it is simply to be mentioned 

 that the various specimens found as a fossil in the neighbourhood 

 of Tokyo and Yokohama all agree with those now living in the 

 Japanese waters. From the foregoing species, the present one is 

 distinguished by its shorter and more swollen form. The largest 

 specimen (right valve) in our collection measures 40 millim. in 

 length, 29 millim. in height and 10 millim in depth. 



Fossil occurrence: — Yokosuka Zone (Otsu); Upper Musashino 

 of Musashi, Kazusa and Shimpsa. 



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

 Indian Ocean. 



156. Tapes amabilis, (Philippi). 

 Pl. IX. Fig. 7. 



Tapes amabilis. Lischke, Jap. Meeresconch., vol. Ill, p. 82, pl. VI, figs. 5-7. Dunker, 

 Index Moll., p. 206. Sowerby, Thes. Conch., II, p. 680, fig. 11. 



Yenuft amabilis. Philippi, Abbild. Ill, p. 75, Venus, pl. VII, fig. 2. 



Several, though incomplete, specimens of an externally con- 

 centrically furrowed Tapes agree fairly well with the one described 

 by Lisluke as a variety of Tapes amabilis Phil. 



The Japanese specimens of Tapes amabilis show a great re- 

 semblance to Tapes schnettianus DunkePv (Nov. Conch., p. 75, pl. 

 XXV, figs. 7-9) also found in the Japanese waters. By examin- 

 ing the recent examples of the two, Tapes amabilis is longer and 

 more flattened than Tapes schnettianus, and the palliai sinus in the 

 former is rounded at end, while in the latter it is truncate. But 

 in our fossil specimens whose form is exactly like that of 

 Philippi species, the sinus is also truncate like that of Dunker 

 species. It is of course not yet certain whether this character is 

 constant or not, but it shows at least that not much weight can be 

 laid on the form of the sinus in distinguishing the two. 



Fossil occurrence: — Naganuma Zone (Naganuma). 



Living: — Central and W T estern Japan. 



