[222] Memoir on Fossil Xanthidia, by Henry Deane, Esq. Microscopical Journal, 1846.

The real nature 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 examine.

VENTRICULITES.

Ventriculites.[223] 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 structure 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 resemblance 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; figs. 3, 6, 8, are fungiform; fig. 7, is the upper part of a specimen, the stem having been broken off; figs. 2 and 4, are examples of the lower part of the zoophyte; in all, there are openings at the base, and a groove on the margin or edge of the upper part in which the structure of the inclosed fossil is visible; upon breaking these flints, sections of a funnel-shaped body are exposed.

[223] Ventriculite; from ventriculus, a ventricle or sac.

Lign. 80. Flints, deriving their forms from Zoophytes.
From the South Downs, near Lewes; 1/6 nat.

Fig.1.—Choanites (?) Turbinatus.
2, 3,4, 6, 7, 8, 9.—Flints, whose forms are derived from Ventriculites,
provincially called "petrified mushrooms."
5.—Spongites labyrinthicus.
10.—Spongites flexuosus.