253 



A»I>i:^DA. 



XYLOVEAG A— TURTON. 



Testa ovato-globosa, eBquivalvis, antici hiantissima, postice clausa, 

 accessoriis cardinalibus instructa. Cardo edentulus infra mnrginem. 

 Ligamentum nullum. 



Shell globular-oval, equivalve, very open at the anterior side and 

 closed behind, furnished with accessorial valves about the hinge. 

 Hinge without the long curved tooth under the margin. Li- 

 gament none. 



XyLOPHAGA. dorsalis. 



Tab. nost. 2, fig. 4 and 5. 

 Teredo dorsalis. Turton, Conch. Diet. p. 185, and p. 16 of this 

 work. 

 We have lately had opportunities fully to examine and elucidate 

 this new and interesting genus, important as it adds to our know- 

 ledge of those singular inhabitants of wood and stone, essentially 

 differing from all other bivalves, in being furnished with accessorial 

 valves or appendages, and which additional valves appear to stand 

 as substitutes for the permanent ligament. 



