UPPER, OR FLINTY CHALK. 177 



expanded and contracted state, is very analogous to what has been 

 noticed in the shape of the recent actinia mesembrt/anthemiim under 

 similar circumstances, (vide note in page 175.) 



Smith's figure is an excellent representation of the usual appearance 

 of the outer surface of the conical specimens. Mr. Parkinson's resembles 

 a cast of the interior ; he describes it " as being composed of chalk, and 

 having somewhat of a conical figure, the surface closely beset with small 

 depressions pretty regularly disposed in a quincuncial order." 



Localities. Upper chalk, near Lewes. 



20. Ventriculites qiiadrangularis. Tab. xv. fig. 6. 



Spec. Char. The animal capable of contracting itself into a quadran- 

 gular form ; the meshes of the external integument circular, very minute ; 

 inner surface ? Stirps •.? 



The specimen represented is the only one hitherto discovered; the 

 quadrangular form into which it is coUapsed distinguishes it from every 

 other species. 



Locality. Upper chalk, Off ham. 



21. VentricuUtes Benettia. Tab. xv. fig. 3. 



Spec. Char. Inversely conical; meshes of the external integument, 

 oblong, irregular, rather distant ; inner surface covered with circular 

 depressions ; margin of the cavity broad, smooth, and nearly flat ; base 

 fixed by radical fibres. 



The form and appearance of this species are so well expressed in the 

 engraving, that a brief description will suffice. It is distinguished by the 

 large, irregular, oblong meshes, of the reticulated surface, and the broad 

 smooth border of the ventricular cavity *. The lower part of the speci- 

 men figured is sihceous, and a radical process is seen issuing from the 

 base. 



I have named this beautiful species in honour of Miss Benett, of Nor- 

 ton-house, near Warminster, Wilts ; a lady of great talent, and indefatigable 



* It must, however, be remarked, that the thickness of the parietes of this species^ renders it 

 probable that its powers of contraction and expansion were very inconsiderable : in this re- 

 spect, it resembles the choanites ; but the reticulated external integument, and the structure of 

 the inner surface, seem to warrant its being retained in the present genus. 



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