84 
NAUTILUS biangulatus. 
TAB. CCCCLVI1X- fig. 2. 
Spec. Char. Discoid, subglobose, with a 
large umbilicus, and a keel upon each side. 
The inner whorls of this Nautilus are half exposed, for 
each following whorl covers the preceding one as far as 
the keel upon its side, the front is rounded ; the aperture 
is transversely elliptical, with the extremities angular in 
young, but obtuse, in old shells ; its width equals two 
thirds of the diameter of the last whorl. 
Occurs in the Mountain Limestone near Bristol ; the 
specimens are in the Collection of the Rev. Dr. Reeke, 
Dean of Bristol. 
