BRACmOPODA. 



221 



ORTHIS, Dalman (as restricted). 

 I. Group of Orthis callactis, Dalman. 



* 0. costalis, Hall Chazy. 



f * 0. orthambonites, Billings Quebec. 



* 0. Euryone, Billings Quebec. 



* 0. Hippolyte, Billings Quebec. 



* 0. disparilis, Conrad Trenton. 



* 0. tricenaria, Conrad Trenton and Hudson River. 



* 0. flabellulum, Sowerby Niagara. 



* 0. Davidsoni, de Verneuil Niagara. 



*0. 



* 0. 

 *[?]0. 



* 0. 



* 0. 



* 0. 

 *[?]0. 



* 0. 



* 0. 



* 0. 

 [??] 0. 



PLECTORTHIS 



(nom. propos). 



II. Group of Orthis plicatella, Hall. 



sequivalvis, 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. Winohell Hudson River. 



dichotoma, Hall Hudson River. 



aurelia, Billings Lower Devonian. 



t This species was identified by Billings witli 0. ort/iambonites. Pander ; but that author used Ortham- 

 BONiTES only as a generic term, thougrh it was subsequently taken by von Bdch and von Eichwald as a 

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

 therefore, be accredited to von Buck, 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. calligramma, var. ortJiaiiibotiites, de Vei'neuil, 

 with which the Quebec species is conipai'ed by Mi'. Billings, and it should therefore receive a new name. 



