[Illustration: Lign. 78. Spiniferites Reginaldi. (_Magnified 500 diameters_.)] [Illustration: Lign. 79. Spiniferites palmatus; in flint. (× 500 _diameters_.)] The apparently torn and collapsed state of the body and arms of some examples first led me to doubt the siliceous nature of the original substance; and on my discovery of the soft parts of foraminifera in flint and chalk, Mr. Deane undertook to search for the so-called Xanthidia in chalk, that these bodies might be subjected to chemical analysis,[221] Mr. Deane succeeded in detecting all the usual species in the Dover chalk, by digesting some chalk in dilute hydrochloric acid, and mounting the residue in Canada balsam. In this state the shape of the body is that of a depressed sphere; many of the specimens appear to have a circular opening, and the arms or spines to be closed at the extremities. Upon pressure 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.[222] [221] A torn and apparently shrunken specimen from chalk, is represented in my paper on Foraminifera; _Philos. Trans._ 1846, p. 465. [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. * * * * * [Sidenote: VENTRICULITES.]