407 



Influenced by almost similar reasons, I shall here introduce some 

 remarks on that fossil wood, which is so frequently found on the 

 shore of Essex, as well as on the opposite shores, which, being hol- 

 lowed out into tubular cavities, apparently by the labours of the 

 teredo, has been distinguished by the name of Lapis Syringoides. 



Representations of specimens of this stone are exhibited at 

 Plate VIII. Fig. 8, 9, 10, where the devastating labours of this 

 animal are sufficiently apparent. 



It may not be amiss to remind you, that, from the time of Theo- 

 phrastus, the lignivorous powers of this creature have been known 

 and dreaded. Linnaeus describes it as a terebella, possessing two 

 calcareous hemispheres for cutting out, and two for piercing ; its 

 round bending shell piercing into the wood. Dr. Baster describes 

 its head as being of a most wonderful structure, being covered with 

 two hard shell-like hemicrania ; but of a substance, in reality, nei- 

 ther osseous nor testaceous. These hemicrania, which are whiter 

 than the rest of their bodies, he speaks of as exceeding in hardness 

 the testaceous tube they inhabit: their inner surface, he describes, 

 as being hollow and smooth ; and the outer, convex and rough, 

 having three ranges of fibres, passing in different directions. These 

 two hemicrania, which are connected by strong ligaments, and, as 

 it were, by a small hinge, by which they are able to dilate, without 

 separating, besides defending the soft head, are the instruments by 

 which the animal procures its food : since being placed in a manner 

 similar to a double bit of that kind of borer we call an augur, 

 whichever way the head is turned, the raised and rough fibres, 

 either of one direction, or of the other, rub off some of the parti- 

 cles of the wood*. 



In the year 1?30, the persons appointed to take care of the dykes 

 on the coast of Holland and Zealand, observed that the piles made 



* Philosophical Transactions, Vol. XLI. Part I. No. 455. 



