150 TJNI VALVES TEREDO. 



tber obtuse or blunt at the tip; it varies in lengtli from 

 four to six inches. This is the worm which was origi- 

 nally imported from India, it has the faculty of boring 

 through, or penetrating the stoutest oaken planks of ships' 

 sides; and is thought to effect as much destruction in the 

 water, as the termes or white ant on land. 



Tlie Teredo utriculus is also cylindrical, undulate, and 

 solid; it is mostly found in wood that has lain sometime 

 under water. It is white, subpellucid, very much bent, 

 and gradually tapering, with an oval aperture, divided 

 in the middle by a partition. It is about seven inches in 

 length. 



'I'lie next and last species is the Teredo clava, which 

 is found in the seminal vessels of the xilosteum grana- 

 tum; one end is clavate, the other incurved, narrower, 

 obtuse, and perforated in the middle: the shell is rough, 

 and brownish on the outside, but within it is smooth, 

 and more or less flexuous. It is nearly two inches long, 

 but not half an one wide. 



TEREDO. — Ship-tvorm. 



*Navalis {Common S. W.) Utriculus. 



Clava. 



