This zoophyte, to which the name of _Ventriculite_ has been given to denote its usual shape, was a hollow inverted cone, terminating at the base in a point, whence radicles or root-like processes were sent off, by which the animal was firmly attached to the rock. The outer integument was disposed in meshes like a net (see _Lign. 26, fig. 1_), and the inner surface was beset with regular circular openings, the orifices of tubular cells (_fig. 2_); each of which was probably occupied by a polype. The substance of the _Polyparium_, or general support of this family of animalcules, which alone occurs in a fossil state, appears to have been analogous to that of the soft _Alcyonia_, and to have possessed a common irritability; the entire mass contracting and expanding, as is the case in many recent zoophytes.[AQ] [AQ] See '_Wonders of Geology_,' 6th Ed., p. 610; '_Medals of Creation_,' p. 273-276; and '_Geological Excursions round the Isle of Wight_,' pp. 179-184, for an account of the silicification of these and other Zoophytes. The flints, _figs. 3, 7, 8, 9, Lign. 25_, were evidently formed in the manner exemplified in _fig. 3, Lign. 26_; _figs._ 2, 4, 6, are illustrated by _fig. 4, Lign. 26_; for the chalk specimens, _Lign. 26_, shew that all these flints have been moulded around _Ventriculites_, and that their diversity of figure has arisen from the quantity of silex that happened to permeate the substance of the zoophyte; if but a small portion, flint like _figs._ 2 and 4, were the result; if the quantity were considerable, the larger fungiform examples were produced. Note IX. Page 50. _Minute Corals from Chalk._ Some layers of chalk are composed of an aggregation of many kinds of delicate corals, the interstices being filled up with _Rotaliæ_ and other foraminiferous shells. In the cliffs near Dover there are several beds of this nature, well known to collectors for the profusion of exquisite specimens they yield to the experienced investigator. _Lign. 17_, p. 50, represents several varieties from different localities; the small figures shew the natural size, and the enlarged ones their appearance when magnified. Attached to the surface of shells, and sometimes standing erect in crannies of flint nodules, beautiful corals may often be detected by the aid of a lens of moderate power. By brushing chalk in water, and examining the deposit, delicate fossils of this kind may also be obtained.[AR] [AR] Refer to '_Medals of Creation_,' p. 284, and to '_Wonders of Geology_,' _Lecture VI._ p. 588, for a comprehensive view of Recent and Fossil Corals. [Sidenote: NATURE OF CORALS.]