283 
[Foerste. 
arated by equally curved grooves so as to give the longitudinal out- 
line of the shell an undulate appearance. The specimen shows no 
signs of tapering in the length preserved, being 26 mm. in diam- 
eter. The finer, transverse striae of this species were not noticed. 
Orthoceras (Sptroceras ?) Jamesi, Hall and Whitfield. 
(plate yii, fig. 3.) 
The specimen here described was obtained from the same local- 
ity as the type, the iron ore beds of the Clinton group, at Todd’s 
Fork, Clinton County, O. It is 11 mm. long, has a diameter of 13.7 
mm. at the smaller end and of 15 mm. at the larger extremity. 
One septum is noticed at a distance of 3 mm. above the smaller 
end of the specimen, this end having separated along one of the 
septa. Another septum is indicated at a distance of 6 mm. above 
the smaller end. The breaking away of the shell for a short dis- 
tance along a line 9 mm. above the smaller end suggests that a 
septum also existed here, so that it is pretty fair to infer that septa 
in specimens of this size occur at intervals of 3 mm. It is be- 
lieved that intermediate septa do not occur since the cast of the in- 
terior of the shell near the smaller end of the specimen, exposing 
all the space between the first two septa described, does not give 
any indication of any intermediate septa. The septa are moder- 
ately concave forming an arc of about 86°. The siphon, as well 
as can be determined, is apparently central or sub-central. Its 
character could not be ascertained. The surface of the shell is or- 
namented by transverse striae, stationed at not very regular dis- 
tances apart. These striae also vary somewhat in size, the various 
sizes irregularly alternating. About eight of these striae occupy 
the length of three chambers in our specimen. Corresponding to 
the stronger of these striae on the surface of the shell, are similar 
transverse, but usually broader elevations on the casts of the inte- 
rior of the shell. The transverse striae are crossed by longitudinal 
striae, much more regularly disposed, usualty 1 mm. apart in speci- 
mens of the size described. Alternating with the longitudinal 
striae are single, much finer striae. A few indications of finer, 
transverse striae were found, but nothing comparable to the num- 
erous, regularly-disposed transverse striae, figured in the type spec- 
imen, was seen. 
