498 MM. Chapman & Sherborn—Foraminifera of the London-clay. 
must in the former have been fixed more firmly in its shell than in 
the latter, and that in all probability the shell-muscles were not 
limited to the sides of the animal, as in the recent JVautilus, but 
completely encircled it. 
The difference between the shell-muscles of Celonautilus and those 
of the recent Nautilus strongly supports the view that the two forms 
are generically distinct, a conclusion already arrived at from the 
great dissimilarity in the form of their shells by such an eminent 
authority as Prof. Hyatt. The subdivision of Nautilus was, in fact, 
begun long ago by M‘Coy? and continued by Meek,? the latter of 
whom expressed his decided opinion that such divisions should at 
least rank as distinct subgenera. 
Under surface of the head of Nautilus pompilius, with the mantle divided and the 
funnel turned back to expose its cavity and the shell-muscles. 
a. a. The divided portions of the mantle; 4. 6. Sheaths of the tentacles ; ¢. ¢. The 
funnel; d. Its valve; e. e. Shell-muscles; jf. f. Their terminations or 
surfaces of attachment; g. The transverse fibres connecting them. 
VIJ.—ForaMInIFERA FROM THE Lonpon Cxay oF SHEPPEY. 
By Freprrick CuapmMan and C. Davies SHERBORN. 
N the Proceedings of the Geologists’ Association for 1878,* Mr. W. 
H. Shrubsole, F.G.S., published a list of Foraminifera obtained 
from the London Clay of Sheppey. The following list, the result of 
an examiuation of some material courteously lent to us by Professor 
J. W. Judd, F.R.S., adds considerably to the fauna of Sheppey and 
includes two species not previously recorded from the London Clay. 
Forty-one forms have been determined, of which twenty-six* are 
new to Sheppey, thus bringing up the number of forms recorded 
from that locality to eighty-six. The geographical distribution of 
the Foraminifera of the London Clay was fully tabulated in 1886,° 
1 Synopsis of the Carboniferous Limestone Fossils of Ireland, 1844. 
* United States Geol. Survey of the Territories, 1876, vol. ix. p. 490. 
5 Proc. Geol. Assoc. vol. v. no. 7, p. 355, 1878. 
4 Numbers 4~9, 11, 13-15, 19-23, 26-30, 38, 386-41, of the list appended. 
® Sherborn and Chapman, Journ. R. Microsc. Soc, [2], vi. 1886, p. 759; and 
ibid. 1889, p. 483. 
