72 Dr. Mantell on Fossil Foraminifera. 
bered structure of that of the Nautilus, is essentially different ; 
for while in the shell of the latter, the animal occupies only the 
outer chamber, and all the internal compartments are successively- 
quitted empty dwellings, in the Polythalamia the body distinctly 
fills up stmultancously all the cells. When the shell is remove 
by weak hydrochloric acid, the soft body is exposed, and is seen 
to extend to the innermost chamber ; and there is a connecting 
tube occupying the place of the siphuncle of the Nautilus, but 
which is the intestinal canal; for the cells of the shell contain 
the receptacles of the digestive sacs or stomachs, in which minute 
Infusoria (as Monads, Navicule, &c. ) that have been swallowed 
y the animal, may sometimes be observed. 
In the fossils, the appearance of the parts which I suppose to 
be the digestive organs, is that of a series of bladders or sacs, 
composed of a tough, flexible skin or res ta connected by a 
tube. ‘These organs are more or less fille 
stance ; those which are distended are always hdlkeaatiogd, while 
the empty ones are collapsed and disposed in folds, just as mem- 
branous pouches would appear under similar conditions. The 
sacs regularly diminish in size from the outer to the innermost 
cell, and vary in number from fourteen to twenty-six ; being far 
more numerous than in the recent species. In some instances 
the interior of Fig. 2. 
xp 
testinal canal are as perfect as 
an individual recently dead, 
and just taken out he sea 
The folds of the sacs that. are 
the duplicatures produced by 
the shrinking, or corrugation, 
of a flexible integument. The 
outline of the shell is but dimly 
visible, and can only be render- 
