130 
ORTHOCERA undulata. 
TAB. LIX. 
Spec. Char. Shell oval, thin, smooth; septa 
numerous, oblique, their edges rising, oval, 
with a wave on each side. Siphuncle near the 
tipper edge. 
The septa are nearly parallel, and but slightly concave, 
there are five or six to an inch, all equally distant: the 
siphunculus, placed near the broad side at about one-sixth 
part from the edge, is about one-tenth of an inch in diameter, 
the shell diminishes about one inch in a foot. My fragment 
is six inches long, and one inch three-fourths by one inch 
and an half wide at the broadest end. 
When the shelly part (which is replaced by Limestone 
as well as the rest of the specimen), is separated, the divi- 
sions of the chambers are shown by distinct transverse striae. 
Fig. 1 shows the undulation opposite to the Siphuncle; 
Fig. 2, the side view, shows the obliquity of the septa; 
Fig. 3 one of the solid casts of the chambers, a little 
concave and with an undulating margin interrupting the 
more regular oval which it would have on looking directly 
into it. The upper part of Figs. 1 and 2 was possibly 
the terminal chamber, as the transverse septa are not to be 
seen; or it may be that the stone is more incorporated 
with it. This is from near the water-force on Scaleber 
near Settle, by favour of Mr. Ducket. 
