Fossils from the Miura Peninsula and its Immediate North 



w 



A single left valve, 16 inilliiii. in length, 10 millim. in height 

 and 5 millim. in depth. It is moderately thick, convex, very 

 inequilateral, trapezoidal, posteriorly broadened, anterior side very 

 short, ornamented with about twelve radiating ribs which carry 

 spines on the posterior ones. The ventral margin is somewhat 

 concave. The specimen represents a young state of the species. 



Fossil occurrence: — Miyata Zone (Shimo-Miyata). 



Living: — Central Japan. 



173. Cardita cumingiana, Dunker. 

 Pl. X. Fig. 16. Pl. XI. Fig. 1. 



GaYdita cumingiana. Dünker, Moll. Jap., p. 29, pl. Ill, tig. 18. Index Moll. p. 221. 



This is a species closely allied to the preceding one, but is dis- 

 tinguished by a greater number of ribs which are fifteen or sixteen, 

 rarely more. These ribs, which in their nodulous or even 

 spiny character resemble those of Cardita variegata, are more or 

 less inverted v-shaped in the anterior portion of the shell, while 

 posteriorly they become more rounded. The anterior ribs, more- 

 over, often possess a weak longitudinal furrow on both sides of 

 their declivities and near their base, so that they appear to sub- 

 divide into riblets. 



Whether Cardita leana Dunker (Moll. Jap., p. 29, pl. III. rig. 

 17) is only a variety of this species, as thought by Pilsbry (Oat., p. 

 135), is a question which I can not decide at present. 



Frequent. 



Fossil occurrence. — Yokosuka Zone (Otsu and Vokosuka). 



Living. — Central and Western Japan. 



Genus Vrnericardia, LAMARCK. 



174. Venericardia cipangoana, Yokoyama. 



Pl. XL Fig. 2. 



Veneric inlia compressa. Yokoyama, Verstein. a. d. jap. Kreide, Palaeonto^raphica,, vol. 

 XXX VI, p. 196, pl. XXV, tig-. 4. 



