Antediluvian Zoology and Botany. 269 
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Ventriculites. — Mr. Mantell has investigated this previously 
obscure class of fossils, and illustrated their peculiar conform- 
ation by an extensive suite of specimens in his Geology of Sussex. 
V. radiatus Mantell, tab. x. Chalk. 
He conceives that this 
animal (for it really ap- 
pears to be one animal, 
rather than a congeries) 
possessed the powers of 
dilatation and contraction 
of its disk, which ac- 
counts for the almost 
infinite variety of form 
which individuals of the 
same species are seen to 
present. (fig. 55.) It is 
fair to state that Dr. 
Fleming objects to this 
hypothesis, and is dis- 
inclined to remove them 
from the Spéngiz. Cer- 
tainly the recent Spongia 
otaheitea of Lamarck, also those of Ellis (tab. 59. figs. 1, 2, 3.), 
bear an extraordinary resemblance to the Ventriculites. 
Mr. Rose has furnished us (Vol. IIL. p. 335—339.) with 
several other illustrations of this zoophyte. The following 
figure from Mantell, tab. xiv. fig. 2. represents Ventriculites 
radiatus, having the external surface completely expanded, 
( fig. 56.) 
