332 TEREDININiE. 



and often concameratecl by numerous, incomplete, transverse 

 partitions. 



Syn. Cyphus, Guett. Kuphus, Gray. Kyphus, Agassis. 

 Furcella, Ohen. Septaria, Lam. Clausaria, Mice. Cloi- 

 sonnaria, Ferns. Malleolus, Gray. 



Ex. T. Norvegica, Spengler, pi. 90, fig. 6. Shell, 

 T. Norvegica, fig. 6, a, 6, h. Tube, T. Norvegica, fig. 6, c. 

 Stylet, T. Norvegica, fig. 6, d. T. palmulata, fig. G, e. 



The Teredines are found in most seas, living in wood, 

 which they perforate by means of the mechanical attrition 

 of their valves; their burrows are usually tortuous and 

 formed in the direction of the grain ; .the perforations are 

 lined by calcareous matter, and the individuals carefully 

 avoid the burrows of their neighbours. They are useful 

 agents in breaking down and destroying fragments of wrecks 

 and floating timber, which might otherwise be dangerous 

 impediments to navigation ; but at the same time they often 

 do incalculable mischief to dikes, submerged piles, and the 

 timbers of ships. The young "Ship-worms" swim freely 

 about, and are even able to float at the surface of the water. 

 M. Laurent has shown that the Teredines are ovo -viviparous, 

 the eggs being hatched in the body of the parent, and the 

 young fry being ejected from the upper siphonal tube. 

 The shell and tube in the sub-genus Xylotrya are the same 

 as in Teredo, but the stylets are pectinate or dentate at the 

 edges ; and in TJperotis, which has similar valves and stylets, 

 the tube is contorted and club-shaped, from the animal 

 being found burrowing in the husks of cocoa-nuts floating 

 in tropical seas. In the Teredo giyantea of Linnajus (the 

 Sej)taria arenaria of Lamarck) the apex of the thick, 

 shelly tube is divided at the end by a longitudinal septum, 

 and is produced into two separate tubes. In the fossil 



