TRANSACTIONS OF THE SECTIONS. 119 



introduced into Europe from the Indies was contrary to fact as well as theory, be- 

 cause no " littoral " species belonging to tropical seas has ever been found living 

 in the northern hemisphere, or vice versa. It is true that some species have been 

 occasionally imported into this and other countries in ships' bottoms, and that 

 others occur in wood which has been wafted thither by the Gulf and other oceanic 

 currents ; but the former cases belong to littoral species, and never survive their 

 removal, while the latter may be said to be almost cosmopolite. Every species of 

 Teredo has its own peculiar tube, valves, and pair of " pallets," the latter serving the 

 office of opercula, and by their means the animal is able at will to close completely 

 the entrance or mouth of the tube, and thus prevent the intrusion of crustacean 

 and annelidan foes. The length of the tube is, of course, equal to that of the 

 animal, which is attached to it by strong muscles in the palletal ring, and varies 

 in the different species from three inches, or even less, to as many feet. The in- 

 ternal entrance or throat of the tube is also distinguishable in each species by its 

 peculiar transverse laniinje, and it has frequently a longitudinal siphonal ridge. 

 Monstrosities occasionally occur in the valves and pallets ; and in one instance the 

 pallet-stalk is double, showing a partial redundancy of organs, as exemplified by 

 the author with respect to the operculum of the common whelk. More than one 

 species often inhabit the same piece of wood ; and want of sufficient care by natu- 

 ralists in extracting the valves with their proper tubes and pallets may account in a 

 great measure for the confusion which exists in public and private collections, and 

 which has thence found its way into systematic works. The Teredines have many 

 natural enemies. In the South of Italy, and on the North African coast, they are 

 esteemed as human food. In Great Britain and Ireland, four species occur in fixed 

 wood, and eleven others in drift wood, the latter being occasional visitants. Of 

 these, no less than six have never yet been described, and two others are now, for the 

 first time, noticed as British. The number of recorded exotic species only amounts 

 to six more, making a total of twenty-one ; but it is probable that, when the subject 

 has been more investigated, a considerable addition will be made to this number. 



Mr. Jeffreys then explained the distribution of the littoral species on the shores of 

 Great Britain and Ireland, and produced a synoptical list with descriptions of the 

 new species. He believed all the Teredines were marine, except, possibly, Adanson's 

 Senegal species, and one which had lately been found in the River Ganges, the 

 water of which is fresh for about eighteen hours out of the twenty-four, and brackish 

 during the rest of the day ; but as a well-known exception of the same kind occurs 

 in a genus of marine shells (Area), and the transition from fresh to brackish, and 

 thence to salt water, is very gradual, such exceptions should not be regarded with 

 suspicion or surprise. He concluded this part of the subject by exhibiting some 

 drawings and specimens, and acknowledging his obligations to Dr. Lukis and other 

 scientific friends. 



He afterwards treated the subject in an economical point of view, and remarked 

 that, although the French Government had issued two commissions at different 

 times, and the Dutch Government had lately published the report of another com- 

 mission, which was appointed to inquire into the mode of preventing the ravages 

 of the Teredo in the ships and harbours of those countries, our own Government 

 had done nothing. He alluded to the numerous and various remedies which had 

 been proposed, during the last two or three centuries from time to time, some of 

 which were very absurd ; but he was of opinion, from a study of the creature's 

 habits, that the most effectual preventive would be a siliceous or mineral composi- 

 tion, like that which has been proposed by Prof. Ansted for coating the decomposing 

 stones of our new Houses of Parliament, or simply a thick coat of tar or paint, 

 continually applied, which would not only destroy any adult ship-worms then 

 living in the wood, but prevent the ingress of the fry. The Teredo never com- 

 mences perforation except in the larval state *. 



A Committee of the Association was formed, at the suggestion of Mr. Jeffreys, 

 to inquire and report as to the best mode of preventing the ravages of Teredo and 

 other animals in our ships and harbours. 



* See also Papers by Mr. Jeffreys on this subject in the ' Annals of Natural History ' 

 for August and October 1860. 



