Plate XVI. 



Figs. 1, 2. Pectunculus vestitus Dkr. Adult specimens from Ötake. 1. Eight 



valve. 2. Left valve. P. 189. 

 Fig. 3. Do. YouDg right valve from Tega. P. 189. 

 Figs. 4, 0. Pectiincnlus yamakawai Yok. 4. Plight valve. 5. Left valve. Shitö. 



P. 19Ü. 

 Figs. 6, 7. Pectunculus yessoensis Sow. (5. Left valve. 7. Ptight valve. Sliito. 



P. 189. 

 Figs. 8, 9. Pectunculus pilsbryi Yok 8. Left valve. 9. Eight valve. Shitö. P. 



190. 



