1 ]^g Art. 1. — M. Yokoyama : 



Class SCAPHOPÖDA. 

 Family Dentalinidae. 



Genus DEIVTALIIJ.H, Linné. 



170. Dettfaliunt tveinhaußii, Dunker. 

 PI. VT. Fio-. 6. 



DentaUiim aeinkauifii. Dnnker, Ind. Moll , p. 153, pl. V, fig. 1. Pilsbiy, Catalogue,. 



p. 116. In Tryou's Man. Couch., XYII, p. 40, pl. II, fig. 26. Yokoyama, Foss. 



Miura Peuin., p. 102, pl. VI, fig. 19-21. 

 Dentalium cf. weinkaiißi. Tokunaga, Foss. Env. Tokyo, p. 33, pl. II, fig. 16. 



The ribs which are present only on the apical portion of the 

 shell are often unequal, being then alternately large and small. 



Specimens are very frequent at some places, as at Otake and 



Shito. 



Fossil occurrence. — Otake, Shisui, Kioroshi, Tega, Shito. 

 Shinagawa in Musashi. Lower Musashino of Naganuma, Koshiba, 

 Kanagawa, and Miyata. 



Living. — Central Japan. 



177. Dental in til oetoyonutn, Lamarck. 



Dentaliam octuyunum. Lamarck, Anim. sans Yert., V, p. 344. Lisclike, Jap. Meeres- 

 coucli , II, p. 103, III, p. 75, pl. Y, tigs. 1-3. Dnnker, Ind. Moll., p. 153. Schrenck, 

 Moll. Amnrl. u. J. nordjap. Meeres, p. 381. Brauns, Geo). Env. Tokio, p. 95. 

 Tokunaga, Foss. Env. Tokyo, p 33, pl. II, fig. 15. Yokoyama, Foss. Miura 

 Penin., p. 103, pl. YI, figs. 22-24. 



This Dentalium already known by the names of B. octangula- 

 tum, D. hexayonum and D. sexcostatum is represented by a few 

 fragments which are either six-, eigiit-, or nine-sided. The angles 

 are ribbed in some specimens, having several liner riblets between. 



Fossil occurrence. — Otake and Shito. Oji and Shinagawa. 

 Lower Musashino of Miyata, Yokosuka and Naganuma. 



Living. — Northern. Central and Western Japan. China, Aus- 

 tralia, Ceylon. 



