﻿535 



has, according to my notes, and when seen from the side, a general 

 resemblance to Nephriticeras qriens. 



The sutures and position of the siphuncle and form of whorl 

 places it in this genus. 



Nephriticeras oriens. 



Nautilus oriens, Hall (Pal. N. Y., v, Pt. ii, PL lxi, and Suppl., 

 PL cvi). 

 This species is obviously closely allied to Nephriticeras magister 

 and maximum. The shell shows coarse longitudinal ridges and stri- 

 ations of growth as in other species of this genus, and the sutures 

 and position and structure of siphuncle also justify its associations 

 with these species in the same genus. 



Nephriticeras inelegans. 



Gyroceras (Naut.) inelegans, Meek (Pal. Ohio, i, PL xxi). 



This form is closely allied to magister and is probably a species 

 of this genus. 



Eudoceratidce. 



This family was described in my Genera of Fossil Cephalo- 

 pods, and again in "Carboniferous Cephalopods," Fourth Annual 

 Rep. GeoL Surv. Texas, p. 465. 



The genera are of interest in this paper because of the absence 

 of the impressed zone in the more generalized open-whorled Eda- 

 phoceras, its appearance as a contact furrow in Endolobus and its 

 appearance as a dorsal furrow in Potoceras dubium. I have placed 

 this last form in this family with much reservation. The young 

 have characteristics similar to those of Endolobus Avonensis, but 

 the development is more advanced and decidedly tachygenic. 



The absence of a dorsal furrow in the nepionic whorl of so highly 

 specialized and so involute a shell as Ephippioceras is upon the 

 whole rather remarkable and requires confirmation with a better 

 preparation than the one at my command. The highly digonal 

 form of the young has induced me to transfer this genus from the 

 Apsidoceratidae, under which it appeared in my Genera of Fossil 

 Cephalopods, to this family. 



Edaphoceras. 

 This genus was first described by the author in Genera of Fos- 

 sil Cephalopods* the type being a large Carboniferous species 



*Proe. Bost. Soc. Nat. Hist., xxii, 1SS3, p. 2SS. 



