206 Teredo navalis and Limnoria terebrans 



Art. V. On, the occurrence of the Teredo navalis and Limnoria 

 terebrans, in Plymouth Harbour. By E. Moore, M.D. F.L.S. 

 Secretary to the Plymouth Institution. 



In a paper " on burrowing and boring animals," by Mr. Os- 

 ier, in the 4th part of the Philosophical Transactions for 1826, 

 it is stated that "the Teredo navalis is probably quite extinct 

 as a British animal, as it is no longer to be found in Falmouth 

 or Plymouth Harbours ; and that he was shewn, in the royal 

 dock-yard at Devonport, specimens of wood bored by the 

 Teredo, treasured as a curiosity, being assured by Mr. Church- 

 ill, the builder, that the animal was no longer to be met with." 



It must not, however, be considered from this observation, 

 that the Teredo has become extinct, as I shall presently shew 

 the contrary ; and it should have been mentioned that the 

 cause of its apparent disappearance was owing to the outer 

 piles of timber in the dock-yard jetties, having been coated 

 with broad-headed iron nails, which is a good remedy against 

 the attacks of this animal. It is well known by residents, 

 that the Teredo has always been existing here, and might at 

 any time have been observed by examining fixed timber in 

 other parts of the harbour, which had not been protected. — 

 I possess specimens of wood taken from an embankment here, 

 which are tenanted by the Teredo, and to which I shall after- 

 wards allude ; the officers of the dock-yard also can testify, 

 that the precautions taken have not been entirely effectual, as 

 the wood work of the jetties is constantly requiring renewal, 

 its destruction being caused, in a great measure, though not 

 entirely, by the Teredo. Mr. Churchward, the inspector of 

 the carpenters, possesses specimens of the animal, which he 

 obtained two years since ; and I have within these few days 

 obtained, through the kindness of Mr. Walker, a piece of oak 

 plank, 2 feet long and 7 inches wide, just taken from the piers 

 at Froward Point, in Plymouth yard, which contains eleven 

 perforations of these animals, many of which are now contain- 

 ed in the specimen. 



Mr. Osier, considering it an imported animal, states that it 

 is not likely to become naturalized, because, from being an in- 

 habitant of warm climates, and always residing near the sur- 

 face, in situations left dry by the ebb tide, it could not with- 

 stand a severe winter. On the contrary, I seldom find the 

 Teredo above low water mark ; its ravages being mostly com- 

 mitted under that point : and it will be found that where it 

 has penetrated higher within the timber, the perforation by 

 which it entered is generally below it. 



I have now, however, to announce that our harbour is ex- 

 posed to the attacks of a much more formidable enemy, the 



