198 UNIVALVES TEREDO. 



head of the animal, resembling the Pholas ; it also has 

 two smaller valves of an ovate form, at the other extremi- 

 ty. The destructive eJfFects of this little animal would 

 frequently occasion the loss of the largest vessels, were 

 it not from the singular fact of their generally perforat- 

 ing the wood in the direction of the grain. 



The T. utriculus is also cylindrical, undulated, and 

 solid ; it is usually about seven inches in length, and 

 found in wood that has lain some time under water. It 

 is white, subpellucid, very much bent, and gradually 

 tapering ; the aperture is ovate, divided in the middle 

 by a partition. 



The last species is the T. clava, which is found in 

 the seminal vessels of the Xylocarpus Granatum ; one 

 end is clavate,the other incurved, narrower, obtuse, and 

 perforated in the middle : the shell is generally flex- 

 uous, and has a brownish color; the exterior is rough, 

 but within it is perfectly smooth. It is nearly two 

 inches long", and about half an inch in diameter. 



The generic name Tfpr/Sa)v (Teredo) is derived from 

 Tepid), to bore. 



Scieniijic Name. Locality. Common Name. 



Gigantea • Sumatra, Ceram Gigantic Teredo 



Navalis Sides & bottoms of Ships Ship do • • 



Utriculus Wood in the Sea Timber • • • do • • 



Clava Coromandel Club-shap'd do • • 



