BRACHIOPODA. 



223 



ORTHOSTROPH I A, Hall. 1883. 



VI. Group of Orthis strophomenoides, Hall. 



*[?J0. fhsciata, Hall Niagara. 



* 0. Halli, Safford Lower Helderberg. 



* 0. strophomen- 



oides, Hall Lower Helderberg. 



PLATYSTROPHIA, King. 1850. 



VII. Group of Orthis biforata, Sclilotheim. 



* 0. biforata, Schlotheim Chazy — Clinton. 



* 0. acutilirata, Conrad Hudson River. 



* 0. crassa, James Hudson River. 



* 0. laticosta. Meek Hudson River. 



* 0. lynx, VON Eichwald Hudson River. 



HETERORTHIS 



(noni. propos). 



VIII. Group of Orthis Clytie, Hall. 



* 0. Clytie, Hall Trenton. 



BILOBITES, LiNNE. 1775. 



IX. Group of Orthis biloba, Linne. 



* 0. biloba, Linne Niagara. 



* 0. varica, Conrad Lower Helderberg. 



DALMANELLA 



(nom. propos). 



X. Group of Orthis testudinaria, Dalman. 



* 0. Electra, Billings Quebec. 



*[?J0. Evadnie, Billings ,. Quebec. 



