BRACHIOPODA. 



221 



R T H I S, Dalman (as restricted). 



I. Group of Orthis callactis, Dalman. 



Hall Chazy. 



* 0. costalis, 

 f* 0. orthambonites, Billings Quebec. 



* 0. Eurjone, 



* 0. Hippolyte, 



* 0. disparilis, 



* 0. tricenaria, 



* 0. tiabellulum, 



* 0. Davidsoni, 



Billings Quebec. 



Billings Quebec. 



Conrad Trenton. 



Conrad Trenton and Hudson River. 



SowERBY Niagara. 



DE Verneuil Niagara. 



* 0. 



* 0. 

 *[?J0. 



* 0. 



* 0. 



* 0. 

 *[?]0. 



* 0. 



* 0. 



* 0. 

 [??]0. 



PLECTORTHIS 



(nom. propos). 



II. Group of Orthis plicatella, Hall. 



aequivalvis, Hall Trenton and Hudson River. 



plicatella, Hall Trenton and Hudson River. 



Ella, Hall Hudson River. 



fissicosta. Hall Hudson River. 



Jamesi, Hall Hudson River. 



Kankakensis, McChesney Hudson River. 



sectostriata, Ulrich Hudson River. 



triplicatella, Meek Hudson River. 



Whitfieldi, N. H. Winchell Hudson River. 



dichotoma. Hall Hudson River. 



aurelia, Billings Lower Devonian. 



t This species was identified by Billings with 0. orthambonites. Pander; but that author used Ortham- 

 bonites only as a generic term, though it was subsequently taken by von Bcch and TON Eichwalu as a 

 sjiecific designation to include all the species referred by Pander to this genus. As a specific term, it must, 

 thei-efore, be accredited to von Buch, and it is synonymous with some one (it is impossible to say which) of 

 Pander's species. It appears to be quite distinct from the 0. calUgramma, var. ortJiamhmiites, de Vei-neuil, 

 with which the Quebec species is compared by Mr. Billings, and it should therefore receive a new name. 



