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spread themselves over the whole inner surface of the animal 
(Fig. 1). An absolutely limpid and transparent fluid fills up 
the interstices, and this it is which imparts, or rather maintains, 
for the animalcule its general rounded form. Should this fluid 
accidentally make its escape through the minutest aperture, 
the animalcule immediately loses its shape and sinks to the 
bottom. The reader may form some conception of the general 
appearance exhibited by the remarkable internal structure of 
Noctiluca by a reference to Figs. 1 and 3 ; but in order to 
understand the strange spectacle which it presents in the living 
animal, it is absolutely necessary to watch the latter with 
persevering attention. It then becomes evident that neither 
the prolongations, nor yet the central mass from which they 
radiate, have any fixity of shape; that they are in continual 
motion, and susceptible of constant modifications. The larger 
branches are seen under the microscope to become attenuated, 
in consequence of the substance of which they are composed 
passing into the neighbouring ones ; whilst the minute ramifi- 
cations assume larger proportions, inasmuch as they borrow 
the materials from others in their vicinity. Here and there 
vacuoles make their appearance, and increase in dimensions, 
whilst others previously existing diminish in proportions, and 
are finally lost to view. 
It will also be observed, that some of these vacuoles are 
formed near the orifice ; that they inclose or surround * gra- 
nules of green substance, or the powder of carmine or indigo, 
which may have been mixed with the water ; then, detaching 
themselves by degrees from the central mass, glide along one 
of its chief prolongations and fulfil the functions of a temporary 
stomach ; for they rotate with this alimentary pillule round the 
whole body, and finally return to the point from whence they 
originally departed.! In short, the little mass and its exten- 
sions are found to consist entirely of sarcode, that primary 
animal substance so carefully studied by the late lamented 
Dujardin, in the external prolongations Gromia, Miliola, and so 
many other of the marine and fluviatile Rhizopoda.J And 
* Or, as the author more appropriately designates it, “ englober,” a word 
for which we have no equivalent in English. 
f In the articles just referred to (“ Lowest Forms of Life”) we had occasion 
to describe these “ vacuoles” as temporary receptacles for the nourishing fluid 
of the body ; indeed the reader who has paid any attention to the subject 
will no doubt already have come to the conclusion that these ISToctilucae are 
but one degree removed from the lowly organisms described elsewhere. 
t The Rhizopoda of Dujardin, which include the F oraminifera of D’Orbigny, 
are regarded as perfect animals, and form a distinct branch in the classifica- 
tions of zoologists ; but for my part I am convinced that they are only larval 
forms, and that their later stages remain to be discovered. — A. de Q. Such of 
our readers as desire to study the Foraminifera, will have an excellent oppor- 
tunity of doing so on the appearance of Dr. Carpenter’s work, to be published 
shortly by the Ray Society. 
