TEREDO NAVALIS AND OTHER SEA-WORMS. 203 



holes were found in it, and it was in every way perfectly sound. 

 The greenheart timber, while not coated with barnacles to the 

 same extent, was slightly perforated, more particularly near 

 the edges where sap-wood would be found. 



Two similar pieces of timber remained in the sea under 

 similar conditions for twelve months. The results when the 

 timbers were removed were much the same as above, except 

 that the Jarrah timber had fewer barnacles adhering to it, and 

 the greenheart had more. The latter result would probably be 

 caused by the gradual washing-out of the acrid matter from the 

 surface of the greenheart. 



Mr Hall Scott, of Sir John Jackson, Ltd., has kindly furnished 

 the following information : — 



At Keyham we were troubled with the Teredo navalis and 

 the Chelura terebrans. The latter was really the worse of the 

 two. Within three years of the piles being driven many of 

 them were reduced from 12 or 13 inches square to 4 inches square, 

 which necessitated additional piles being driven alongside each 

 original one. The Chelura eats away the softer parts of the 

 timber, longitudinally, between the annular rings, which fall away 

 in thin flakes as the animal goes deeper. Some of the holes or 

 tunnels made by the Teredo navalis were found to be | inch in 

 diameter, and the timber was riddled through and through, the 

 animals themselves being in some cases id inches long. 



I have had no experience in Scottish waters, but assume that 

 the conditions are very similar to those in England. I have 

 always found the ravages caused by these worms to be worse 

 as the water gets salter ; as an example, at Devonport Dockyard 

 they were distinctly worse than even with us at Keyham, while a 

 little farther up the Hamoase, at Bull Point, where we carried 

 out some work, and where the water was more brackish, they 

 were not nearly so bad as at Keyham. At Mevagissey, in 

 Cornwall, where the water is quite salt, I saw timber which 

 had only been driven some twelve months, and which was 

 absolutely eaten away. 



Mr James Currie, shipowner, Leith, writes : — 

 I am informed that no British port is free from the ravages 

 of this ferocious beast {Teredo). It is said, however, to be less 



