506 ITAJsITAL or THE MOLLuSCA. 



M. teredimformis was found in cakes of floating v/ax on tlie 

 coast of Cuba. (G-. B. Sby.) M. austrcdis in (fossil r) resin, on 

 the coast of Australia. M. rivicola in timber twelve miles from 

 tlie sea, in Borneo. M. scittaia, Eocene, Paris, lines its burrow 

 witli shell. 



Jouannetia (semicaudata), Desm. (Pholadopsis, Conrad ; 

 Triomphalia, Sby.) SJiell ygtj short, sub-globose; right valve 

 longest behind ; anterior opening closed by a callous plate deve- 

 loped from the left valve overlapping the margin of the right 

 valve, and fixed to the single unsymmetrical umbonal plate. 

 Disfrihution, i species. Philippines, "Western America. Fossil, 

 Miocene — . Prance. 



FarajjJiolas, Conrad. P. bisulcata, PI. XXIII. , Pig. 22. Yalves 

 with 2 radiating furrows. JDistrihiition, 4 species. Panama, 

 Torres Straits. 



Xylophaga, Turton. 



Etymolocjy , xulon, wood, pliago, to eat. 



Ty]jes, X. dorsalis, PL XXIIL, Pig. 2-3; X. globosa, Sby. 

 Yalparaiso. 



Shell globular, with a transverse furrow ; gaping in front, 

 closed behind ; pedal processes short and curved ; anterior 

 margins reflected, covered by 2 small accessory yalves ; buiTov/ 

 oval, lined with shell. 



Animal included within the valves, except the slender con- 

 tractile sij^hons, which are furnished with pectinated ridges, and 

 divided at the end ; foot thick, very extensile. 



Distrihution, 2 species. Norway, Britain, South America. 

 Bores an inch deep, and across the grain, in floating wood, and 

 timbers which are always covered by the sea. 



Tehedo (Pliny), Adanson. 



Type, T. Norvegica, PL XXIIL, Pigs. 26, 27. 



Synonyms, Septaria, Lamarck. Hyperotis, Gruettard. ■* 



Shell, globular, open in front and behind, lodged at the inner 

 extremity of a burrow partly or entirely lined with shell ; valves 

 3 lobed, concentrically striated, and with one transverse furrow ; 

 hinge-margins reflected in front marked by the anterior muscu- 

 lar impressions ; umbonal cavity with a long curved muscular 

 process. 



Animal worm-like ; mantle-lobes united, thickened in front, 

 with a minute pedal opening; foot sucker-like, with afoliaceous 

 border ; viscera included in the valves, heart not pierced by the 

 intestine; mouth with palpi; gills long, cord-like, extending 



