SIPHONIA. 231 
_ Siphonia closely resembling this species ; and varied sections 
_ of its stems produce the white markings commonly observable 
on the slabs of pavements. 
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Lien. 73. SIPHONIZ, FROM THE GREENSAND; nat. 
Wilts, and Isle of Wight. 
Fig. 1.—SIpHONIA PYRIFORMIS; the body or upper part. 
2.—Vertical section of the same, showing the internal structure, and 
the central cavity. 
3.—Specimen of S. pyRIFORMIS in a young state. 
4.—SIPHONIA (Polypothecia, of Miss Benett,) LopaTa; Firestone or 
Upper Greensand, Warminster. 
5.—The lower part of the stem, and radicles, of S. pyRIFORMIS. 
A group of Sponges from the Upper Greensand, near War- 
minster, figured and described by the late Miss Etheldred 
_ Benett,* under the name of Polypothecia, comprises several 
* An elegant Memoir on the Wiltshire Fossils, by this accomplished 
lady, is published in Sir R. C. Hoare’s “ Wiltshire.” 
. 
