77 



NAUTILUS regalis, 



TAB. CCCLV. 



Speo. Char. Gibbose, plain, not umbilicate; 

 front flattish ; sides convex ; aperture rather 

 wider than long. 



X 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 soHd 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 regalls, 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^tratum, and is accompanied by 

 vertebral columns of Pentacriuites subbasaitifonnis.* 



* Aliller's Natural History of Crinoidea, p. 140. 



