TEREDO. 71 



Plymouth examples, and Turton, who furnishes an admi- 

 rable diagnosis from specimens living in a tree of British 

 oak, regained at Teignmouth after a long immersion, satisfy 

 us by their descriptions that it is not only indigenous, or, 

 at least, long naturalised, but that it is the true T. nor- 

 vagica of Spengler, a fact not ascertainable from the lan- 

 guage or the drawings of any of our previous writers upon 

 British Conchology ; the delineation in Donovan's "British 

 Shells," vol. v. pi. 145, and that in Pulteney's "Dorset 

 Catalogue, pi. 18, f. 21, being equally suitable to any 

 species of this genus. In truth, the microscopic scrutiny, so 

 peculiarly demanded for the valves of this genus, has rarely 

 been bestowed upon them ; writers of the Linujean school, 

 both British and foreign, (with the honourable exception of 

 Spengler,) contenting themselves with classing all the ship- 

 worms under the one appellation navalis, describing the 

 tube, but neglecting the more important anterior valves and 

 the characteristic pallets. But whether extinct or not in 

 those spots from which our cabinets were formerly supplied, 

 its devastations are continued to the present day in the little 

 harbour of Port Patrick, on the coast of Wigtonshire, where 

 several of the piles used in the formation of the pier have been 

 materially injured, and some even utterly destroyed. The 

 tubes in this locality had, in some cases, attained the ex- 

 traordinary length of nearly two feet and a half; and the 

 valves of three-quarters of an inch in diameter. Mr. 

 Thompson, in the interesting paper* from which we have 

 derived our knowledge of this habitat, thus describes 

 them : — 



" The greatest diameter of the testaceous tube or case, at 

 the larger end, is seven-eighths of an inch ; at the smaller, 

 it varies from one and a half to two lines. All of the spe- 



* W. Thompson, in the Edinburgh New Philos. Journal, January, 1835. 



