NArXILID.^. 
317 
and the central position of the siphiincle nearly resembles the recent 
Nautili. It is a very ventricose, almost a globose shell, much 
rounded on the ventral aspect ; the aperture is bluntly lunate, 
nearly semicircular, and is rather more than twice as wide as it is 
long ; the open umbilicus is narrow and deep ; the septa are con- 
cave outwardly, and simple, scarcely presenting any undulation or 
second curvature whatever ; the dorsal lobes are broad, each being 
nearly one third of the width of the aperture, and they are bluntly 
rounded on their superior margins ; the siphuncle is very small, 
central, or nearly so, and continuous. The lines of growth present 
broad undulations, and are strongly marked and decussated. 
“ Michelotti has described a Nautilus from the Miocene formations 
of the Colle de Torino, in Piedmont, to which he has given the 
name Bucldandi. He quotes N. centralis of Sowerby by the name 
X. australis (an error into which he has fallen by relying on 
Defrance’s quotation), and he considers his shell to be identical 
with it, and, oddly enough, associates with it X. imperial is. The 
specific description given by this author agrees tolerably well with 
that of the present species ; but I have not myself had any oppor- 
tunity of comparing the Piedmontese with the English shells ; and 
as Michelotti does not mention his having compared the two, and 
he appears to have trusted implicitly to Defrance, the accuracy of 
the identification must for the present be considered as doubtful.” 
(Edwards.) 
llemarhs. This species is easily distinguished from Xautilus 
rerjalis by its inflated form and the greater width of the aperture 
compared with the height. It comes nearer to X. impericdis, from 
which species, however, it differs in its greater width and closed 
umbilicus. 
“ This species,” remarks Edwards, “ does not appear to have 
attained a great size, the largest specimen not exceeding 3'7 inches 
in diameter, by 3-3 across.” “ It occurs,” he adds, “ at Regent’s 
Park, Chalk Earm, Hyde Park, Richmond, Sheppey, and Bognor ; it 
is also found, though very rarely, at Bracklesham Bay.” 
Horizon. London Clay (Lower Eocene). 
Localities. Whetstone, Chalk Earm, Hadley, Maida Hill (London) ; 
Middlesex : Isle of Sheppey : Bognor, Bracklesham, Sussex. 
Well represented in the Collection, which contains the specimen 
(No. 69651) figured by Edwards (Mon. Pal. Soc. pi. hi. f. I), and 
also the one figured by Dixon in the ‘ Geolog}" of Sussex,’ pi. xiv. 
f, 28. 
