ARCTIC ORDOVICIAN AND SILURIAN CEPHALOPODS 305 
28. Orthoceras Sp. 
Plate XXXIV, fig. 3 A, B 
On the Fossil Faunas from Per Schei’s Series B in South- 
western Ellesmer eland, Rep. Second Norwegian Arctic Expedi- 
tion, in the ^^Fram^’ 1898-1902, No. 32, 1914, p. 32. 
Fragment 15 mm. long, consisting of a single camera 3.5 mm. in 
length, surmounted by the lower part of a living chamber 17 mm. 
in length. No trace of the aperture is present, so that the original 
length of the. living chamber can not be determined. Moreover, 
the single camera present is so long that the conch probably is 
immature, so that the size of a mature specimen also remains 
unknown. The suture of the septum inclines at an angle of about 
75 degrees with the vertical axis of the conch from the dorsal 
toward the ventral side of the conch. This suture is almost 
straight, with a slight tendency toward horizontality along the 
middle of the lateral sides. The cross-section of the conch is 
transversely elliptical. The lateral diameter being 14 mm., and 
the dorso-ventral one slightly over 11 mm. The ventral side 
is distinctly more flattened than the dorsal one. The septum 
is quite evenly concave, the depth of the concavity being 2.5 
mm. At its passage through the septum the siphuncle is 2.3 
mm. in diameter; its center is 6 mm. from the dorsal margin of 
the septum and an equal distance from the ventral margin, but, 
measured in a direction strictly transverse to the vertical axis 
of the conch, it is 5 mm. from the dorsal side of the latter and 
6 mm. from its ventral side, thus being slightly dorsad of the 
center of the conch. A vertical section through the center of 
the camera failed to reveal any trace of the siphuncle except at 
its passage through the septa. The septal neck apparently 
was confined to a slight downward inflection of the septum. 
The surface of the shell appears to be smooth. 
Locality and Horizon. — Valley south of Borgen in Goose 
Fjord, in southwest corner of Ellesmer eland. From the frag- 
mental limestone in the' upper part of series B of Per Schei. 
Collected by Per Schei June 28, 1902, and deposited in the 
Paleontological Collections of Kristiania University. 
