XYLOPHAGA. 17 



merely because Dr. Turtoii, who first described the genus^ 

 called it " X?/lophaga." This Xylophaga is a little mollusc 

 resembling the Teredo in many respects. Like the latter^ it 

 penetrates wood that has been immersed in salt water for 

 any length of time. It does not make a long hole, because 

 its tube, containing the alimentary canals, is very short, and 

 it only makes an oval hollow to live in. The shell is only 

 open in front, not in front and back, as in Teredo, and it 

 has not the curved bones under the beaks which are seen in 

 other Pholads, The beaks or umboes of the valves are pro- 

 tected by two little plates, which are called accessory valves. 

 The pallets are pen-like, and the hole is never lined with any 

 shelly tube. The first specimens of Xylopliaga dorsalls were 

 obtained by Dr. Turton, from the fragments of a wreck 

 which had been submerged nearly fifty years ago, near Berry 

 Head, Torbay ; and in the ^ Annals of Natural History' for 

 1847, an interesting account is given of another locality, by 

 Mr. Thompson, whose notice gives an excellent idea of the 

 nature and haunts of the species. 



"Early in the month of May last. Major Martin of Ar- 

 drossan, in Ayrshire, a gentleman well known as a lover of 

 natural history and as a successful collector of objects of 

 zoological and botanical interest, sent me a piece of wood 



c 



