102 
VENTRICULITES. 
lands of the Downs, and which bear considerable 
resemblance to a quoit ; their origin is, however, 
satisfactorily illustrated by the specimen figured 
p. 101. In this example the ventriculite is in- 
verted, and is attached to the chalk by its inner 
surface, the outer integument forming a narrow 
zone round the annular flint which, in the perfect 
state of the fossil, encircled the stem. 
The appearance of this specimen seems to 
warrant the conclusion, that at the period of its 
mineralization the silex was in the state of a thick, 
viscid fluid, otherwise it is difficult to understand 
why it should not have extended to the margin 
of the zoophyte, instead of being consolidated in 
its present situation. A cyathiform flint, in my 
cabinet, might also be adduced in support of such 
an opinion, in which tlie silex not only fills the cavity 
of the ventriculite, but is elevated considerably above 
the margin, as if a pulpy or glutinous fluid had been 
gradually poured in till the cup-like cavity was 
overflowing. 
In concluding this description, it may be proper 
to offer a few remarks on the probable economy of 
the recent animal ; and, from the facts that have 
been presented to our notice, endeavour to illus- 
trate the nature of the original. 
From a careful examination of a numerous and 
interesting suite of specimens in my ])ossession, 
the structure of the recent ventriculite may be 
readily understood. The general form of the 
animal ap})ears to have been that of a hollow in- 
verted cone, having numerous ramose fibres ]>ro- 
ceeding from the base, by which it was attached 
