UPPER, OR FLINTY CHALK. 173 



to a block of chalk ; the impressions of numerous radical processes are 

 seen at the base. 



Tab. xiii. fig. 1 . The upper part of a ventriculite preserved in flint, 

 the side of the cavity being somewhat collapsed. 



Figs. S, 3. 5 ; chalk specimens of the stem or inferior part ; the moni- 

 liform appearance of the fibres is probably the result of contraction *. 



Fig. 4. A ventricuhte attached to a block of chalk. The lower part 

 is enveloped in flint, but a fracture near the base exposes a portion of the 

 enclosed zoophyte; the upper portion is preserved in chalk, and exhibits 

 the reticulated structure of the external integument. 



Fig. 6. A magnified view of part of the external surface of fig. 2, 

 shewing the lateral filaments or processes. 



Tab. xiv. represents two chalk specimens of Ventriculites radiatus, 

 the animal in both instances being completely expanded. Fig. 1 exhibits 

 the inner surface covered with perforated papillae ; fig. 2 the external 

 surface with its reticulated integument. The radical processes are not 

 seen in this example, having been unavoidably removed with the sur- 

 rounding chalk. 



In concluding this description, it may be proper to offer a few remarks 

 on the probable economy of the recent animal, and from the facts that 

 have been presented to our notice, endeavour to illustrate the nature of 

 the original. 



From a careful examination of a numerous and interesting suite of 

 specimens in my possession, the structure of the recent ventriculite may 

 be readily understood. The general form of the animal appears to have 

 been that of a hollow inverted cone, having numerous ramose fibres 

 proceeding from the base, by which it was attached to other bodies. Ex- 

 ternally it was composed of a muscular reticulated integument, capable 

 of expanding and contracting, according to the impressions it received ; and 



* The flint represented in Sowerbi/'s British Mineralogy, Tab. 215, fig. 3. is a siliceous 

 specimen of the stivps of this species ; but it is drawn in an inverted position : the perforations 

 in the upper part of the figure, are the apertures through which the radical processes passed. 



