49 



It occurs at Junction Cliff and near Jupiter River ; Divs. 1, 2, A. G. J. 

 Richardson. 



Genus Cyrtodonta, Billings. 



C. ACCUTUMBONA, n. sp. — This species is about the size and shape of O. 

 ungulata^ with the difference that the umbones are very strongly cari- 

 nated. The posterior portion of the shell is broken off, and the entire out- 

 line cannot, therefore, be made out. One mile south of Junction CUff 

 Anticosti ; Div. 1, A. G. T. C. Weston. 



Genus Ambonychia, Hall. 



Fig. 16. 



Fig. 16. — Amhony cilia superha. Right valve and anterior view. 



