6 
Mr. W. C. Williamson on the Recent 
truding through the foramina in the calcareous cell, long exten- 
sile tentacula or pseudopodia ; great bundles of filaments, which 
projected from the surface, and especially from the umbilical re- 
gion. These tentacula had also been noticed by M. Alcide D^Or- 
bigny (see the Voyage dans L’Amerique Meridionale, tome v. 
p.29). 
In some further investigations into the structure of these cu- 
rious creatures, in the memoir above alluded to (which is already 
printed), I have come to the conclusion that a more or less dense 
but elastic membrane lines the interior of each cell of the compound 
Foraminifera allied to Rosalina glohularis, Rotalina Beccarii and 
the Textillaria, upon which my observations were chiefly made, 
prolongations of which membrane, injected from within (like the 
processes which the Echinodermata push through the ambulacral 
pores), constitute the pseudopodia observed by Ehrenberg and 
Alcide D^Orbigny ; since, however large and distinct may be 
the foramina in the external calcareous portion of each cell, no 
trace of these foramina can be found in the membrane which 
continuously lines the calcareous portions of the cells, when the 
latter have been removed by acid. This internal membrane ap- 
pears to have been filled with gelatinous matter, having appa- 
rently very little organization — a condition noticed by M. Du- 
jardin, and which led him to regard the Foraminifera as little 
more than an animated slime encased in an external calcareous 
shell, and to associate them with the Pseudopodian Amceha 
amongst the Infusoria. When the outer shell is removed by acid, 
we often find that the different sacs of the inner membrane con- 
tain numerous small siliceous organisms, which the animal ap- 
pears to have swallowed, but which are scattered indiscriminately 
over the whole of the cell in which they occur, and not confined 
to any one line, which would have been the case had there been 
any restricted portion, confined within special and narrow^ limits, 
performing the functions of an intestinal canal. Hence it appears 
probable, that, as in the case of the Hydra and some of the lower 
infusorial animals, the whole cavity of the organism w^as one sac- 
culated digestive organ, the various cells or divisions of wEich, in 
those compound forms which are allied to Rosalina and Rotalina, 
are connected together by one or more tubular necks ; channels 
of communication passing through the septa, and along which the 
food received could pass from one cell to another. How the rejecta- 
menta made their escape is doubtful ; possibty, as is the case with 
the Hydraform Polypifera and many other lower animals, the 
oral orifice may be at once both mouth and anus. 
It will be understood, that, according to these views, the ani- 
mal membrane which is left after the removal of the calcareous 
portion is in reality an exact cast of the interior of the latter. 
