TEREDO. 333 



genus Teredina the valves of the shell are cemented, in 

 the adult, to the walls of the tube; in the other genera the 

 shell remains free at the end of the tube. The use of. the 

 siphonal, spatulate appendages or stylets, according to 

 Clark, is to assist in compressing and relaxing the siphons 

 to facilitate the flow of water through the long canal. 



Sixties of Teredo. 



denticulata, Gray. navalis, Linn. 



dilatata, Stimp. Norvegica, Spengl. 



elongata, Quatref. pedicellata, Quatref. 



fatalis, Quatref. Petitii, Recluz. 



gigantea, Linn. Senegalensis, Desk. 



malleolus, Turt. truncata, Quatref. 

 nana, Turt. 



Sub-gen. xylotrya, Leach (Bankia, Gray). 



Siphonal pallettes elongate, penniform. 



carinata, Leach. Philippii, Gray. 



palmulata, Lam. Stutchburyi, Leach. 



pennatifera, Blainv. 



Sub-gen. upeeotis, Guettard (Guettera, Gray). 



Pallettes ovate, dentate ; tube club-shaped or contorted. 



clava, Gmel. lagenula, Lam. 



corniformis, Lam. 



VOL. II. X X 



