214 



living specimens of this rare species, unmixed with any other, 

 many of which were apparently full-grown and 10 inches in 

 length ; some I examined alive and dissected fresh, and many 

 others from spirits. These facilities have, I think, almost 

 put it in my power to give a tolerably general idea of the 

 animal, though it may not be a complete anatomical detail. 

 Under the circumstances I have stated, I am inclined to think 

 that the following notes may afford malacologists some infor- 

 mation, and enable them to compare my humble attempt with 

 the anatomies of Teredo by the great masters in this branch 

 of science. Agreeably to my usual method I commence with 

 the external description of the animal, and then proceed to its 

 anatomy. 



T. MEGOTARA, Hanley. 

 T. megotara, Brit. Moll. i. p. 77, pi. 1. f. 6, & pi. 18. f. 1, 2. 



Animal vermicular, pale bluish-white, inclosed in a sub- 

 cylindrical elongated tubular mantle, not of very thin texture, 

 only open anteally and posteally. The specimen examined 

 measured 8 inches from the front valves to the terminal 

 pallets, and when the siphons were extended, an inch longer. 

 The anterior part of the animal is inclosed in a pair of hemi- 

 spherical shining white valves, with a large angular gape in 

 front, and rounded behind into auricles, which in this species 

 are much larger than in its congeners ; the body and mantle 

 are fixed to them, and proceed under the protection of a tes- 

 taceous tube to the terminal pallets, which are also encased 

 within the tube. 



It will here be convenient to observe, that the calcareous 

 tube through which the body passes, to be spoken of more in 

 detail hereafter, has hitherto been considered as one of mere 

 protection ; but I shall show that though the globular valves in 

 front work free in the tube, it is as much a part of the animal 

 as the shell of the Pholades, inasmuch as it is fixed to it pos- 

 teriorly by a very strong muscle. 



The branchiae are invisible until the mantle is opened. 

 There is what appears to be a purple dull red labium on each 

 side of the mouth, connected by a thin membrane ; these have 



