224 



and Teredo, &c., from the bottom to the top of the scale of 

 the Bivalves, is not an injudicious procedure. 



The other British Teredines are 



T. NORVEGICA, Spengler. 

 T. norvegica, Brit. Moll. i. p. 66, pi. 1. f. 1-5. 



T. NAVALIS, Linnseus. 

 T. navalis, Brit. Moll. i. p. 74, pi. 1. f. 7, 8, and pi. 18. f. 3, 4. 



The following are exotic : 



T. B i PEN NAT A, Turton. 

 T. bipennata, Brit. Moll. i. p. 80, pi. 1. f. 9-11. 



T. MALLEOLUS, TurtOll. 

 T. malleolus, Brit. Moll. i. p. 84, pi. 1. f. 12-14. 



T. PALMULATA, Lamarck. 

 T. palmulata, Brit. Moll. i. p. 86, pi. 2. f. 9, 10, 11. 



XYLOPHAGA, Turton. 

 X. DORSALIS, Turton et Auctorum. 

 X. dorsalis, Brit. Moll. i. p. 90, pi. 2. f. 3, 4 ; and ii. p. 375. 



We met with this species alive many years since, at Ex- 

 mouth, and greatly regret that it passed unobserved. 



Having inserted a paper in the 'Annals of Natural History' 

 on the Terebrating Mollusca, we will only state, that it is now 

 generally considered that the foot and fleshy part of the 

 ventral surface of the mantle, aided by the fine sand and 

 siliceous particles that are a part of the animal's attributes, 

 are the excavating agents. See Mr. A. Hancock's excellent 

 Memoir on these points, in the 'Annals of Nat. Hist.,' N. S. 

 ii. p. 225. 



