Lign. 83. Ventriculites alcyonoides. in Flint. Lewes.
Ocellaria inclusa. König.
| Fig. | 1.— | Portion of the surface of fig. 2, magnified. |
| 2.— | The fossil body extracted from the flint, fig. 4. 2a.—Transverse section of the same, showing a central spot of flint, surrounded by tubular cells. 2b.—Two of the cells of fig. 2a, 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.
Until more ample and satisfactory evidence is collected as to the nature of these fossils, the interests of science will be best promoted by allowing the question to remain sub judice, and restricting the term Ventriculites to those zoophytes which possess the general characters of the type to which the name was originally assigned; namely, a vasiform or subcylindrical framework, terminating at the base in a point, and fixed by radicle processes; the substance consisting of a plexiform fibrous tissue; externally constituting a reticulated integument, the meshes disposed in a radiating manner from the base to the periphery; the inner surface studded with open cells regularly arranged.
In the former edition of this work the Ventriculites were placed with the Polypifera from the structure of the openings or cells, for these are so symmetrical, and disposed with so much regularity, as to present a closer analogy to the polype-cells of a coral, than to the large pores of a sponge. The doubts expressed by many eminent observers as to the correctness of this view, have induced me to insert this notice in the present section; leaving the true affinities of these organisms to be determined by future observers. Possibly we have in these fossils the relics of a tribe of zoophytes of an extinct type, that formed a connecting link between the porifera and the polypifera; however this may be, I will venture to affirm that no one who had seen the infinitely varied examples of these fossils that I have, would for a moment confound them, as some naturalists have done, with the Scyphiæ, and other simple amorphozoa.