TEREDO. 73 



element a few clays ago, are of equal size to those sent from 

 the same place five years since, shewing that it has not been 

 aifected by the cold of the winter season, as we might rea- 

 sonably expect were the animal truly exotic. If this animal 

 had been originally introduced, and has been preserved only 

 by occasional importations, should we not rather look for it 

 in those ports of the United Kingdom where vessels from 

 every quarter of the globe are congregated, than in the ob- 

 scure harbour of Portpatrick, which has never been visited 

 by a foreign craft." 



That the species is not extinct also in England, was clearly 

 proved during a recent visit to Torquay,* when a large stalk 

 of timber, to which the cables of vessels were wont to be 

 attached, having been removed as unsound, a living speci- 

 men was extracted from it, and several individuals have 

 since been discovered in the same log, and forwarded to INIr. 

 Hanley by Mrs. Griffiths, with the important information 

 that it was by that species the late destruction of the bridge 

 at Teignmouth had been effected. Almost all our evidence 

 tends to prove that the T. norvagica, so far from being 

 an exotic species, imported from warmer climates, and lin- 

 gering for a few generations in our less congenial waters, is 

 actually more abundant as we proceed northwards, its dis- 

 tribution extending to England and other temperate coun- 

 tries of Europe, where it propagates now at least, even if 

 not strictly indigenous from the most ancient periods. 

 Nevertheless, it must be regarded as one of our rarer shells, 

 the greater number of collections being only provided with 

 individuals taken from ships' timbers and other foreign 

 sources, and very few indeed with specimens derived from 

 the piles of jetties, submerged trees, or other legitimately 

 indigenous habitats. Hence great caution is required in 



• S. H, 



VOL. I. L 



