Chalk and Flint of the South-east of England. 83 
Society do not read works of so unpretending a character, and 
may consider this statement as startling and unsatisfactory ; I 
therefore claim the indulgence of entering upon a few details to 
render the above remarks more intelligible. 
It must be borne in mind that the case or shell of the Rotalia, 
although presenting the general form, and the internal chambered 
structure, of the shell of the Nautilus, is essentially different ; for 
the whole of the external case is perforated with numerous holes 
or foramina (hence the name Foraminifera), designed for the pass- 
age of delicate processes called pseudopodia, which are organs of 
motion ; and the cells or chambers are dissimilar in form, and still 
more so in their office, from those of the Cephalopoda. For while 
in the Nautilus the animal occupies only the outer chamber, and 
all the posterior compartments are successively-quitted empty 
dwellings, in the Rotalia the body distinctly fills up all the single 
cells. According to Ehrenberg, the first four cells in the living 
animal are occupied by colourless matter ; the hinder ones are 
filled with less transparent parts, consisting of two differently co- 
loured organs. One of these is the very thick alimentary canal, 
which forms, like the whole body, a jointed chain expanded in 
each chamber of the shell, and connected by a narrow isthmus 
(the sipho ?) with the adjoining anterior and posterior ones. 
M. Ehrenberg dissolved the shell of a hvmg polythalamian, 
nearly allied to the Rotalia (the Nonionina germanica), by im- 
mersion in weak hydrochloric acid, and thus exposed the ali- 
mentary canal, which was then seen to be a simple organ dis- 
tended in the compartments of the body, consequently itself ar- 
ticulated with a single anterior aperture; and various siliceous 
infusoria were distinctly perceived in the digestive tube, having 
been swallowed by the animal. Beside the alimentary canal, 
a yellowish brown or amber-coloured granular mass was percep- 
tible in each of the cells, up to the last of the spirals, the first 
excepted. 
It was the striking resemblance between the specimen first 
submitted to my notice, and the figure of the Nonionina deprived 
of its shell, as given by Ehrenberg, that led me to suspect the 
true nature of the fossils under review ; and the exquisite example 
which will be placed under the microscope for the inspection of 
those present, appears to me to leave no doubt of the correctness 
of that opinion. In the same chip of flint there is another and 
larger Rotalia, in which the body of the animal also is pre- 
served. And now that we are accustomed to the microscopical 
appearance of these organisms, we find that the pale yellowish 
brown, or amber colour, of many semidiaphanous flints is derived 
from the soft parts of Rotalia, Textilaria, and other polythala- 
mian animalcules; in like manner, as I showed in a paper read 
