NAUTILID^. 
295 
steeply sloping sides and rounded borders ; the inner whorls partly 
exposed. The whorls present a subtriangTilar outline in section, 
owing to the flattening of the sides and the superior width of the 
dorsal as compared with the ventral or peripheral side. The septa 
are moderately distant, being about 7 lines apart where the height 
of the whorl is inch. The sutures are slightly bent backwards 
on the sides of the shell, and form a shallow sinus on the peripheiy. 
Fig. 66. 
yautilus Bayfieldi. — a, lateral view of a specimen, showing the umbilicus and 
the ribs ornamenting the test ; b, peripheral view of another specimen, 
showing sutures (s) and ribs. Drawn from specimens in the British 
Museum {a, No. C. 3103 ; b, No. C. 3102), about two thirds natural size. 
There appears to be an inner lobe. The siphuncle is situated a 
little below the centre. The test is ornamented with numerous 
acute transverse ribs or plications, separated from each other by 
spaces about equal to their own width. The ribs form a deep sinus 
in crossing the periphery. 
RemarTcs. “ This species is closely allied to Nautilus patens, Kner 
from which, however, it differs in its more compressed whorls, 
smaller umbilicus, and the position of its siphuncle, which is below 
^ ‘ Versteinerungen des Kreidemergels von Lemberg und seiner Umgebung,’ 
p. 7, tab. i. figs. 2, 2 a. See also Dr. Clemens Schliiter, “ Cephalopoden der 
oberen Deutschen Kreide,” in Palacontograpbiiia, Band xxiv. Lief. 1. April 187fi, 
p. 178, Taf. 1. 
