28 CONCHIFERA. 



Class CONCHIFERA. 



* 



Head indistinct; moiitli 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 the body, usually compressed and keeled. Valves of shells 

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

 dividual bisexual. 



" FaxMily PPICLADID.E, Leach. 1819. 



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

 ture ; without hinge or ligament, often strengthened by additional 

 valves. 



Ocnus 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, descending much below 

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

 emarginate at tip. 



Teredo marina, Sellius, Hist. Nat. Tcrcd. tab. 2, figs. 2, 3, 6. 



Teredo navalis, Lin., Syst. Nat. 1267. — Forbes and H.\nl., Brit. Moll. i. 74, pi. 1, figs. 

 7, 8 ; pi. 18, figs. 3, 4. — Hanley, Shells of Lin. 450. — Sowerby, 111. Br. Shells, 

 pi. 1, fi<r. 1. — Tryox, Proc. Ac. Nat. Sc. Phil. (Sept. 18G2), 468, where also may be 

 foiuul the synonymy in lull. 



This is the curious shell which 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. 



