NAUTILIDJE. 
321 
strongly than tliose of the two preceding species, and their undu- 
lations are broad and shallow. 
“ The Nautilus urhanas is distinguishable from N. centralis by its 
flatness, and the greater length [or height] of its aperture; and 
from N. regalis by its open umbilicus, the truncated extremities of 
the dorsal lobes of the septa, and its discoidal shape. It is a very 
rare shell. The figures 2 a, 2 tab. iii. [Edwards’s plate] are taken 
from the shells drawn in ‘Mineral Conchology’ [vol. vii. 1843, 
pi. dcxxviii.], the only specimens with which I am acquainted. 
The larger one, belonging to Mr. Sowerby, was found in excavating 
St. Katherine’s Docks, near the Tower of London ; the smaller one 
forms part of Mr. Bowerbank’s collection, and was obtained from 
Sheppey.” {Edwards.) 
Kemarhs. The dimensions of the individual last mentioned are 
inches in diameter and 3^ in width : it is now in the “ Sowerby 
Collection ” (Ko. 44061). A still larger specimen (No. 69646), from 
the London Clay near Whetstone, has a maximum diameter of 
inches. The smaller specimen (No. 71001) is also in the British 
Museum. 
Giebel (Fauna der Yorwelt, Band iii. Abth. i. 1852, p. 152) 
places N. urhanus., J. de C. Sow., as a synonym of N. umbilicaris. 
Deshay es \ but the latter is a much more inflated shell with a 
larger umbilicus than Sowerby’s species. 
Horizon. London Clay (Lower Eocene). 
Localities. St. Katherine’s Docks, London (“ Sowerby Coll.”) ; 
Isle of Sheppey (No. 71001) ; near Whetstone, Middlesex. 
Well represented in the Collection. 
Nautilus imperialis, J. Sowerby. 
1812. Nautilus imperialism J. Sowerby, Min. Conch, vol. i. p. 9, pi. i. 
? 1824. Nautilus Lamarkii, Deshayes, Descr. des Coquilles Fossiles des 
Environs de Paris, vol. ii. p. 767, pi. c. 
1825. Nautilus imperialism Defrance, Diet, des Sciences Naturelles, 
vol. xxxiv. p. 297. 
1836. Nautilus imperialis, VVetlierell, London, Edinburgh, and Dublin 
Phil. Mag. and Journ. Sci. vol. ix. p. 465. 
1849. Nautilus imperialism Edwards, Mon. of the Eocene Cephalopoda 
and Univalves of England, vol. i. (Pal. Soc.), p. 47, pi. v. 
1849. Nautilus imperialis, Dixon, Geology and Fossils of the Tertiary 
and Cretaceous Formations of Sussex, pp. 109, 120, 228. 
^ Descr. des Coquilles Fossiles des Environs de Paris, 1824, vol. ii. p. 767, 
pi. xeix. 
PART II. 
Y 
