CYRTOCEEATIDiE. 
269 
Remarhs. This species is known only by a fragment of the septate 
part of the shell, which measures 4 inches 4 lines along the outer 
curvature, and 2| inches along the inner ; its greatest diameter is 
2 inches 10 lines, its least 1 inch 2 lines. 
Fig. 47. 
Cijrtoccras ohliquum. — a, front view; h, side view, Reduced to about | of tlie 
natural size. From a specimen in the National Collection. 
The only Devonian species comparable with this one is Cyrtoceras 
(^Ooceras) Jiexuosus, Schlotheim, sp., hut the slow rate of tapering 
and the oviform character of the transverse section of the latter 
serve at once to distinguish it. 
Horizon. Stringocephalen-Kalk : Middle Devonian. 
Locality. Gerolstein, Eifel. 
Represented in the Collection by a single imperfect specimen. 
Subgenus MSLOCERAS, Hyatt, emend. Foord. 
This subgenus includes laterally compressed, more or less rapidly 
tapering shells, the section of which is somewhat broadly ovate, the 
narrower part corresponding with the periphery. The siphuncle 
may be external (exogast7'ic), internal {endo gastric), or, more rarely, 
subcentral {medio gastric). The body-chamber is usually short, as 
