BRACHIOPODA. 



221 



ORTHIS, Dalman (as restricted). 

 I. Group of Orthis callactis, Dalman. 



* O. costalis, Hall Chazy. 



t* 0. ortliambonites, Billings Quebec. 



* 0. Euryoiie, Billings Quebec. 



* O. Hippolyte, Billings Quebec. 



* 0. disparilis, Conrad Trenton. 



* 0. tricenaria, Conrad Trenton and Hudson River. 



* 0. Habellulum, Sowerby Niagara. 



* 0. Davidsoni, de Verneuil Niagara. 



* 0. 



* 0. 

 *[?J0. 



* 0. 



* 0. 

 *0. 



*[?]0. 

 *0. 

 *0. 



* 0. 

 [??] 0. 



PLECTORTHIS 



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. orthavihonltes. Pander ; but that author used Ortham- 

 BONITES only .'IS a g^eneric term, thoujjli it was subsequently taken by von Blcii and voN EicuwAH) as a 

 specific desitrnation to include all the species lefeired by Pandkr to this {jenus. As a specific term, it must, 

 therefore, be accredited to voN BuCH, and it is synonymous with some one (it is impossible to say which) of 

 Pander's species. It appeal's to be quite distinct from the 0. calligramma, var. orthambonites, de Verneuil, 

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



