77 
NAUTILUS regalis. 
TAB. CCCLV. 
Spec. Char. Gibbose, plain, not umbilicate ; 
front flattish ; sides convex ; aperture rather 
wider than long. 
-I he volutions of this Ammonite increase rather more 
rapidly in size than those of N. imperialis, which is near 
akin to it, and from which it is further distinguished by 
the solid columella or axis, by the convex, not straight, 
sides of the aperture or section, in the young shells, and 
the expanded sides and straight front of the aperture in 
the adult. 
It is remarkable that the prevailing species of Nau- 
tilus, found at the depth of about 60 feet, in the Regent’s 
Canal, near the White Conduit House at Islington, in 
1815, and also in Hyde Park, should prove different 
from that found at Highgate, and upon the Isle of 
Sheepy, yet numerous specimens prove that fact. 
I have named it regalis, as it seems little inferior in 
splendor to the Imperialis, and nearly equals it in size, 
though it appears from two or three specimens I have 
with small remains of the thickened edge of the aperture 
near the axis, that it is full grown when about nine 
inches in diameter and five in thickness. I believe no 
Author has noticed it. It probably belongs to the lower 
part of the London Clay stratum, and is accompanied by 
vertebral columns of Pentacrinites subbasaltiformis.* 
* Miller’s Natural History of Crinoidea, p, 140. 
