49 



SERPULA? extensa. 



TAB. DCXXXIV.— ^g. I. 



Spec. Char. Nearly straig-lU, faintly corrugated ; 

 shell tliick, tlie greater portion of it free ; 

 aperture round. 



Syn. Serpula extensa, Brand. Foss. Hants. 12. 

 pi. 1./ 12. Morris, Catat. 6(3. 



iHE tube diminishes slowly and regularly until near the 

 apex, when it contracts rather suddenly. The surface is 

 marked with broad, annular, slightly raised ridges, which 

 are numerous and nearly equal; otherwise the shell is 

 smooth; it is composed of several laminae, which together 

 give a considerable thickness. 



Great numbers of solitary fragments of this shell are 

 found in Barton Cliff, but any mark of attachment is rarely 

 met with. It has long been doubted whether these frag- 

 ments may not be portions of the tubes of Teredo antenaut(B\ 

 but the shell of them is thicker than Teredo generally has 

 it, and I am not aware that they are ever found at Barton 

 with remains of wood around them. Clusters of very 

 similar tubes occur at Bognor imbedded in fossil wood ; 

 sometimes they are even more tortuose, and therefore 

 more like the usual form o^ Serpida; in these however the 

 shell is still thin and fragile. The specimens figured are 

 in the cabinet of Mr. Edwards. 



Fig. 1. «. is a magnified representation of a portion 

 showinir the surface of attachment. 



