168 Art. ].— M. Yokoyama: 



',i71. Trape^ititn ventrieosum, Yokoyama. 

 PI. XIII, Fig. 1. 



Shell thick, somewhat higher tlian long, very inequilateral, 

 much swollen, sharply rounded in front, truncate behind, with 

 ventral margin only slightly arclied. Beak very large, swollen, 

 curved forward as well as inward, with two blunt edges, one 

 running to postero-ventral and the other to antero-ventral corner. 

 Space between these two edges flattened. The sculpture consists 

 only of coarse lines of growth. Behind the beak there is a lan- 

 ceolate area-like space bounded by a blunt ridge in each valve 

 Avith three longitudinal ribs on it. Palliai line simple. 



There is only a single left valve with a large part of the beak 

 broken. The hinge is worn by friction, but so much is certain 

 that there is at least one prominent main tooth. The posterior 

 lateral is indistinct. It is 18.5. millim. long, 20 milhm. high and 

 10 millim. deep. 



Fossil occurrence. — Otake. 



272. Tà'ape^itêm livnttun, (Keeve). 



PI. XIII. Fig. 16. 



Trapezium liratum. Pilsbry, Catalogue, p. 136. 



Cypricardia lirata. Eeeve, Couch. Icon., I, Cypricartlia, spec. 1, 



Shell moderatel}'' thick, rather tumid, transversely elongated, 

 strongly inequilateral, sharply rounded in front, truncate behind. 

 Dorsal and ventral margins nearl}^ straight and parallel. A flat 

 ridge runs from the beak to the rounded postero-ventral corner. 

 Surface with a shallow median depression and rugose concentric 

 folds or ridges. Area lanceolete, l)ounded by a ridge on each side. 

 Main teeth two, horizontal; laterals indistinct. Palliai line simple. 

 Only a left valve, 20.5 millim. in length, 12 milhm. in height 

 and 5.3 millim. in depth. 



Fossil occurrence. — Otake. 



Living. — Central Japan. 



