28 CONCHIFERA. 



Class CONCHIFERA.* 



Head indistinct; mouth with elongate fleshy lips or palpi. 

 Body covered with a bi-lobed mantle, each lobe protected by a 

 shelly valve. Gills lamellar, two on each side. Foot placed 

 under tlie body, usually compressed and keeled. Valves of shells 

 united on their dorsal edges by a ligament. Animal aquatic. In- 

 dividual bisexual. 



Family PHCLADID.E, Leacii. 1819. 



Shell gaping at both ends, armed in front with rasp-like sculp- 

 ture ; without hinge or ligament, often strengthened by additional 

 valves. 



Ocmis TEREDO, Lin. 1758. 



Valves equal, largely open at both ends, forming a ring, placed 

 at the larger extremity of a shelly tube open at both ends, and 

 furnished with pallets. 



Teredo navalis. 



Principal diameters equal, posterior auricle expanded, descendinp; much below 

 the anterior triangle, and internally presenting a broad, appressed shelf. Pallets 

 emarginate at tip. 



Teredo marwn, Sellius, Hist. Nat. Tcrcd. tah. 2, figs. 2, 3, 6. 



Teredo navalis, Lin., Syst. Nat. 1267.— Forbes and PL\nl., Brit. Moll. i. 74, pi. L figs. 

 7, 8 ; pi. 18, figs. 3, 4. — Hanley, Shells of Lin. 4,50. — Sowerby, 111. Br. Shells, 

 pi. l', fig. 1.'— Tryon, Troc. Ac. Nat. Sc. Phil. (Sept. 18G2), 4G8, where also may be 

 found the synonymy in full. 



This is the curious shell whicli is so remarkable for perforating 

 holes in timber, giving it a honeycomb appearance. These holes 



* With the few exceptions mentioned by me in foot-notes, all the text of Conchifera 

 was prepared by Dr. Gould. — W. G. B. 



