228 



PALAEONTOLOGY OF NEW YORK. 



The en'Oiieons reference of tliis species has hut, recently been corrected, in ]iart, by Mr. 

 A. F. FoERSTE, t who has pointed out some of the . ilifferences already mentioned, and has 

 proposed to retain the species (as it stands in the list) associated with 0. calligramma, var. 

 flabellites. While indisposed to continue a resupinate shell in this association, the necessity 

 of another name for the American species is evident. 



The following arrangement will indicate the relations of Orthis flabellites to the group of 

 Orthis callactis, Dalman, and that of Orthis pectinella, Enmions : 



ORTHIS, Balman (as restricted). 

 I. Group of Orthis callactis, Dalman. 



* 0. costalis, Halt Chazy. 



* 0. orthambonites, Billings Quebec. 



* 0. Euryone, Billings Quebec. 



Billings Quebec. 



Conrad Trenton. 



CoNR.^D Trenton and 



Hudson River. [. q. flabellites, Hall. Niagara. 



* 0. Hippolyte, 



* 0. disparilis, 



* 0. tricenaria. 



* 0. Davidsoni, 



DE Vernedil Niagara. 



D I N R T H I S . 



IV. (rroup (if Orthis pectinella, Emmons. 



* O. pectinella, Emmons Trenton. 



* 0. pectinella, 



var. semiov.alis, -tlALL Irentou. 



* O. Sweeneyi, N. H. Winchell, Trenton. 



t Proceedings Boston Society Natural History, vol. xxiv, pp. 308-312. 1890. 



The following tabular arrangement of the generic subdivisions of the 

 Outhw^ will show the geological range of eacii one of the subdivisions, and 

 of the entire family : 



