2.--The fossil body extracted from the flint, fig. 4. 2_a_.--Transverse section of the same, showing a central spot of flint, surrounded by tubular cells. 2_b_.--Two of the cells of fig. 2_a_, highly magnified. 4.--The hollow flint, from which fig. 2 was extracted; the papillæ on the surface, are casts of the apertures of cells. ] Ventriculites alcyonoides. _Lign. 83._--Under the name of "_Ocellaria inclusa_," the late Mr. König[227] figured and described an elegant fossil zoophyte not uncommon in the chalk and flints of Sussex. This fossil is inversely conical, and somewhat resembles the cast of the cavity of _Ventriculites radiatus_, but a little attention will enable the collector to distinguish it. The flint that is moulded in _V. radiatus_, is surrounded by the substance of the zoophyte, and if found detached, with the investing material removed, shows no structure whatever, but simply a surface covered with minute papillæ. The present zoophyte is generally included in a nodule, and by a slight blow may be readily separated from the surrounding flint; it then has the appearance of a white calcareous cone, beset with regular cells, disposed in quincunx order (_Lign. 83, fig. 2_); leaving a conical cavity in the flint, which is covered with corresponding eminences (_Lign. 83, fig. 4_). Upon breaking the cone itself, it is found to consist of a dense reticulated structure, from one-eighth to a quarter of an inch in thickness (_Lign. 83, fig. 2a_), investing a solid nucleus of flint, the surface of the latter being covered with minute points, which are less regular than those on the cavity of the outer case. The specific name, _inclusa_, was suggested by this character; which, however, is only accidental, for the specimens imbedded in chalk, are simply surrounded by the stone. It is the calcareous nature of the fossil, which renders it so easily separable from the investing flint, while its cells afford numerous points of attachment, and these remain as casts in relief on the interior of the hollow case: I have not observed the same regularity of structure on the inner as on the outer surface. [227] Icones Foss. Sect. _fig._ 98. The reticulated integument of this zoophyte resembles in structure that of _V. radiatus_. With regard to the latter, I should state that Mr. Toulmin Smith[228] discovered that the inosculating fibres of the intimate tissue formed an octahedral plexus at each knot or point of union; and this structure Mr. Smith regards as peculiar to the Ventriculites, and states that he detected it in all the fossils he has arranged under the name _Ventriculidæ_. No spicula have been detected in the integuments. [228] "On the Ventriculidæ;" a series of papers published in the Annals of Natural History, with many figures of cretaceous zoophytes. By Toulmin Smith, Esq.