539 
has, according to my notes, and when seen from the side, a general 
resemblance to Wephriticeras oriens. 
The sutures and position of the siphuncle and form of whorl 
places it in this genus. 
NEPHRITICERAS ORIENS. 
NAUTILUS ORIENS, Hall (Pa/. WV. V., v, Pt. ii, Pl. 1xi, and Suppl., 
Pl evi): 
This species is obviously closely allied to Wephriticeras 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 (Pad. Odio, i, Pl. xxi). 
This form is closely allied to magzster and is probably a species 
of this genus. 
Ludoceratide. 
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 Pofoceras dubium. I have placed 
this last form in this family with much reservation. The young 
have characteristics similar to those of Exdolobus 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 
Apsidoceratidee, under which it appeared in my Genera of Fossil 
Cephalopods, to this family. 
LEedaphoceras. 
This genus was first described by the author in Genera of Fos- 
sil Cephalopods,* the type being a large Carboniferous species 
* Proc. Bost. Soc. Nat. Hist., xxii, 1833, p. 288. 
