TEREDO. 167 



' Memoires de rAcademie Royale/ Lamarck described 

 the valves as containing a muscle which is protruded at 

 the posterior end, and the pallets as apparently bran- 

 chial ! Both O. F. Miiller and Fabricius had long pre- 

 viously adopted the views entertained by Sellius and 

 Adanson as to the natural position of this mollusk ; 

 each in fact gave the only species known to him the 

 name of Pholas teredo. The familiar and appropriate 

 name of this genus has not escaped the experimental 

 handling of systematists. It is the Siphonium of Browne, 

 Xylophagus of Grono^dus, and Teredarius of Dumeril ; 

 and it has been divided by other writers into minor and 

 more or less equivalent genera. 



11. Indigenous species. — I propose to admit into the 

 list of British Mollusca only such species as inhabit 

 fixed and submerged wood on our coasts, and which of 

 course are really indigenous ; but I consider those found 

 in floating wood, and l^rought from distant parts of the 

 world, as no more entitled to be classed with native 

 productions than Hyalaea (Cavolina) trident at a, seve- 

 ral species of lanthina, or Spirula australis, none of 

 which live in the British seas, although they are 

 occasionally drifted hither by the Gulf stream. Some 

 of the Teredines which pay us a visit in this way, reach 

 our shores in a fresher state than others ; T. megotara 

 frequently, and T. malleolus, T. excavata, T. bijnnnata, 

 and T. cucullata now and then, have the animal entire, 

 although dead or scarcely alive, according to the length 

 of the voyage. 



