942 THE MEDALS OF CREATION. Cuap. VII. 
arms or spines to be closed at the extremities. Upon pres- 
sure under water between two pieces of glass, they were torn 
asunder as a horny or cartilaginous substance would be, and 
the spines in contact with the glass were bent. Some after 
maceration in water several weeks became flaccid ; a proof 
that they are not siliceous.* 
The real n2ture of these fossils must be regarded as still — 
undetermined : their prevalence in the chalk flints whose 
forms are derived from zoophytes, seems to countenance the - 
supposition that the Spiniferites are the gemmules or early 
state of animals of this family ; but I have never detected 
any organic connexion between them and the porifera with 
which they are associated ; it is possible they may be the — 
germs of the remarkable zoophytes we have next to ex-_ 
amine. 
Ventricuuites.t Lign. 80, 81, 82.—At every step of our 
review of the fossil zoophytes, I find myself embarrassed by — 
the conflicting opinions entertained by naturalists, respecting 
some of the most abundant of the extinct forms; arising © 
from the imperfect state of our knowledge as to the struc-— 
ture of the originals, which compels a comparison with recent | 
types, from which, perhaps, the fossils differed essentially in — 
their organization. This remark especially applies to the 
zoophytes which have given rise to the fungiform flints so — 
well known to the inhabitants of the chalk districts of 
Sussex, as “ petrified mushrooms,” from their close resem- 
blance in form to fungi : a specimen with this name inscribed ~ 
on it in the cabinet of a friend first drew my attention to ~ 
these curious fossils. In Lign. 80, figs. 2, 3, 4, 6,7, 8, 9, — 
several flints of this kind are represented ; jigs. 3, 6, 8, are — 
* Memoir on Fossil Xanthidia, by Henry Deane, Esq. Microscopical 
Journal, 1846. , 
+ Ventriculite ; from ventriculus, a ventricle or sac. 
