122 Art. 1.— M. Yokoyama : 



Genus SAXiC'AVA, Fleuriaii de Belle vue. 

 183. Sfiocicavu orieiifnlis, Yokoyaiua. 



Saxicava orientalis. Yokoyama, Foss. Miura Peniu., p. 106, pi. VII, fig. 2, 3. 



A left valve much larger than the specimens hitherto 

 obtained, but not quite perfect. Tlie general shape and the thin. 

 state of the shell are, however, alike. 



Fossil occurrence. — Shito. Lower Musashino of Yokosuka. 



Family Corbulidœ. 



Genus CORBIXA, Bruguière. 



1S4. Co»'6t«l« ertjtiirodoii, Lamarck. 



PI. VI. Figs. 8, 9. 



Corbula erythrodon. Lamarck, Anim. sans Vert., VI, p. 138. Liscbke, Jap. Meeres- 

 conch., I, p. 136. Dunker, Ind. Moll., p. 176. Pilsbry, Catalogue, p. 117. 

 Eeeve, Conch. Icon., Corbvila, pi. I, fig. 4. 



Tliis species is easily recognized by its thick, ovate, nearly 

 equilateral, carinated shell which is concentrically grooved on the 

 surface. A perfect specimen with both valves preserved measures 

 25 millim. in length, 14 millim. in height and 9 millim. in 

 thickness. 



Together with the typical specimens, there occur several 

 which are rather thin-shelled, but without any marked difference- 

 in shape. Such thin-shelled ones occur also among the living, 

 the two being bridged over by intermediate forms. 



Fossil occurrence. — Otake (rare). Kioroshi (do). 



Living. — Central and \Vestern Japan. 



1S5. Coi'buln venustii, Gould. 



Corbula venusta. Gould, Bost. Soc. Nat. Hist., vol. VIII, p. 25. Otia Conchologica, 

 p. 164. Sclireuck, Moll. Amurl. u. d. nordjap. Meeres, p. 505, pi. XXV, figs. 

 1-4. Dnnker, Index Moll., p. 177. Toknnaga, Foss. Env. Tokyo, p. 39, pi. II, 

 fig. 22. Yokoyama, Foss. Minra Penin., p. 107, pL VII, ligs. 4-6. Pilsbry,. 

 Catalogue, p. 117. 



This species which is now living in Nurtliern Japan is- 

 frequent at some localities. 



