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animal throws out tentacula. The body of the shell has an appearance 

 resembling stalactites, and was found filled with a soft gelatinous flesh ; 

 but there appeared no indication of the animal having adhered to any 

 part of the internal surface of the shell, which was in general smooth. 



Rumphius has figured one species of this shell ; but his figure exhi- 

 bits two long jointed tubes, issuing from the upper part of the exterior 

 tube ; and he describes them to be found in shallow water, among the 

 mangrove trees. The shell of Rumphius differs from that of Mr. Grif- 

 fiths, in having the two tubes through which the tentacula pass, of con- 

 siderable length, and entirely separate. 



Sir Joseph Banks, on seeing this shell, had no doubt of its being a 

 Teredo ; and the truth of Sir Joseph's opinion has been since established 

 by the discovery of the two boring shells and the two flattened opercula, 

 which form the decided character of teredines : these, Mr. Home states, 

 were found enclosed in one of the specimens. This shell is therefore con- 

 sidered by Mr. Home as belonging to a new species of Teredo, which he 

 names Teredo gigantea *. 



On examining the Teredo navalis, whilst preserved in sea-water, Mr. 

 Home found that the animal threw out sometimes one and sometimes two 

 small tubes : one of these, about I of an inch long, the other only half 

 that size. In examining the shell, while in the wood, its external orifice is 

 very small, just large enough to give a passage to the two small tubes. 

 The sides of the cylinder are thickest near its origin, becoming thinner 

 towards the head of the animal. 



The head of the animal is enclosed between the two boring shells, which 

 are united together by a digastric muscle. From the middle of the 

 exposed part of the head projects a kind of proboscis, which there is rea- 

 son to believe acts as centre bit. 



.The body of the worm is enclosed in one general covering, extending 

 from the base of the boring shells, with which it is firmly connected, to 



* Description of a rare species of worm-shells, discovered at an Island lying off the North- 

 West coast of the Island of Sumatra, in the East Indies. Philosophical Transactions^ 1806. 



