CEPHALOPODA. 45 
No. 7. NAUTILUS CENTRALIS. Sowerby. Tab. III, fig. la—c. 
Navritus cenrrais, J. Sow. 1812. Min. Con. vol. i, p. 11, tab. 1, left-hand figure. 
= AUSTRALIS (by error for CENTRALIS). Defrance. 1825. Dict. des Sc. Nat. vol. xxxiv, 
p. 297. 
— ceNTRALIS. Wetherell. 1836. Philos. Mag. and Journal, vol. ix, p-. 465. 
= Bucktanvi.(?) Michelotti. 1840. Ind. rag. di alcuni Testacei de Cefal. foss. &e. 
Ann. delle Scien. del Regno Lomb.-Veneto, p. 4. 
—  cENTRALIS. Morris. 1843. Cat. Brit. Foss. p. 182. 
— Pictet. 1845. Traité élément. de Paléont. vol. ii, p. 338. 
pas — Sow. 1849. Dixon’s Geol. Hist. &e. pp. 110, 121, tab. 14, fig. 28. 
NV. testé globosd, in aspectu ventrali rotundatd ; aperturd semilunari ; umbilicatd, 
umbilicis angustis, profundis ; septis extis concavis, simplicissinis, siphone central, 
minimo, continuo perforatis ; lobis dorsalibus latis, haud reflevis. 
The N. centralis, m the simplicity of the septa and the central position of the 
siphuncle, 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 concave 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 
Tormo, in Piedmont, to which he has given the name Buchlandi. He quotes 
LV. centralis of Sowerby by the name JV. 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 VV. zmperialis. The specific description given by 
this author agrees tolerably well with that of the present species; but I have not 
myself had any opportunity of comparing the Piedmontese with the English shell; 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. 
Mr. Wetherell, in his paper above quoted, gives this species and Naut. regalis as 
characteristic of the middle division of the three which he thinks might be made of 
the true London Clay. It occurs at Regent’s Park, Chalk Farm, Hyde Park, Richmond, 
Sheppy, and Bognor; itis also found, though very rarely, at Bracklesham Bay. 
The species does not appear to have attained a great size, the largest specimen not 
exceeding 3°7 in. in diameter, by 3°3 in. across. The figs. 1 and 2, Tab. III, are taken 
from specimens in the collection of Mr. Wetherell; fig. 3, from one in that of Mr. 
Sowerby. The form of the septum is shown by fig. 2, Tab. VIII. 
