AMERICAN PALEOZOIC CEPHALOPODS 
205 
tened and evidently was in contact with the ventral wall of the 
conch, so that the location of the siphuncle must have been endo- 
gastric, as in Clarkoceras. Along the remainder of the contour 
of the siphuncle the septal necks appear to have equalled in 
length the height of the camerae, and to have presented vertical 
outlines within these camerae. In one of the specimens an 
endocone apparently was present. Orthoceras edax shows a 
similar structure. Both Orthoceras missiquoi and 0. edax are 
congeneric with Cyrtoceras quebecense Whiteaves, described 
from Point Lewis, opposite Quebec. The conch of the latter 
species is relatively much more elongated than in typical Clarko- 
ceras; the segments of the siphuncle are cylindrical in form, and 
consist of the septal necks, each of which is one camera in length. 
7. EREMOCERAS (HYATT) FOERSTE 
Genotype: Cyrtoceras syphax Billings. Pal. Foss., vol. 1 ,Geol. Surv. 
Canada, 1865, p. 194, text fig. 178, Foerste, Journ. Sci. Lab. 
Denison Univ., vol. 19, 1921, p. 263, pi. 33, figs. 8 A, B. C; 2 
Eremoceras is a small subfusiform cephalopod, somewhat like 
Cyclostomiceras in form. The dorsal side of the conch is dis- 
tinctly convex lengthwise, while the ventral side is almost 
straight. The camerae are closely crowded. The siphuncle is 
large, and endogastric in location. It is in contact with the ven- 
tral side of the conch for the greater part of its width. In the 
type specimen, the siphuncle is depressed dorso-ventrally, being 
considerably more convex 'along the side facing the interior of 
the conch. Vertical outlines of the septal necks are curved 
slightly inward within the camerae, as in the Endoceratida. The 
genus is known only in Canadian strata. 
Cyrtoceras aristides Billings may be related to Eremoceras. 
The siphuncle is large and in contact with the adjacent wall of 
the conch, and the living chamber apparently contracts toward 
the top. Better specimens than the type are needed for exact 
reference. 
8. CYCLOSTOMICERAS HYATT 
Genotype: Gomphoceras cassinense Whitfield. Amer. Mus. Nat. Hist. 
Bull., vol. 1, 1886, p. 322, pi. 29, figs. 1-3. Ruedemann, New York 
State Mus. Bull., 90, 1906, p. 501, fig. 56; pi. 37, figs. 1-3; pi. 38, 
figs. 5, 6 
Conch subfusiform in outline, the greatest diameter being at or 
immediately below mid-height of the living chamber. The 
