CONCHIFEEA. 483 



Example, S. livida, PI. XXII., Fig. 1. S. diphos, Pig. 2. 

 S. orbiculata, Eig. 3. 



Shell oval, compressed, rounded in front, attenuated and 

 slightly gaping behind ; hinge-teeth f , small ; siphonal inflec- 

 tion very deep, connected with the pallial line ; ligament ex- 

 ternal, on very prominent fulcra. 



Animal, mantle open, fringed ; siphons very long, branchial 

 largest orifices fringed; foot large, broadly tongue-shaped, 

 compressed ; palpi long pointed ; gills recumbent, inner laminae 

 free, dorsal border wide. 



Distribution, 20 species. West Indies, Eed Sea, India, Mada- 

 gascar, Japan ,' Australia, Tasmania, Peru* 



Fossil, 30 species. Eocene — . United States, Europe. 



Semele, Schumacher, 1817. 



Etymology^ Semele, in Greek myth, the mother of Bacchus. 



Synonym, Amphidesma, Lamarck, 1818.* 



Type, S. reticulata, PI. XXI., Eig. 11. 



Shell rounded, sub-equilateral, beaks turned forwards ; pos- 

 terior side slightly folded ; hinge-teeth 2.2, laterals elongated, 

 distinct in the right valve ; external ligament short, cartilage 

 internal, long, oblique ; pallial sinus deep, rounded^ 



JDistrihution, 60 species. West Indies, Brazil, India, China, 

 Australia, Peru. 



Fossil, 30 species. Eocene — . United States, Europe. 



Suh-genera. Cumingia, G. Sowerby. C. lamellosa, PI. XXI., 

 Eig. 12. Shell slightly attenuated and gaping behind, lamel- 

 lated concentrically ; cartilage-process prominent ; pallial sinus 

 very wide. Distribution, 10 species. In sponges, sand, and 

 the fissures of rocks, — 7 fathoms. West Indies, India, Aus- 

 tralia, West America. Fossil, Miocene—. Wilmington, North 

 Carolina. 



Syndosmya, Eecluz. Synonyms, Abra, Leach MS. Erycina 

 ^part), Lamarck, 1805. f Type, S. Alba, PI. XXL, Eig. 13. 

 Shell small, oval, white and shining; posterior side shortest; 

 umbones directed backwards ; cartilage-process oblique ; hinge- 

 teeth minute or obsolete, laterals distinct ; pallial sinus wide 

 and shallow. Animal with the mantle open, fringed ; siphons 



* The name Amphi-desma, as employed by Lamarck, included species of Semele, 

 Zxiripes, Syndosmya, Mesodesma, Thracia, Lyonsia, and Kellia ; in addition to which 

 it has since been applied to some Oolitic Myacites. 



t The nams Erycina was originally applied by Lamarck to a number of minute 

 fossU shells, including sp. of Syndosmya, Venus, Lucina, Tellina, Astarte, and Kellia. 

 In 1808 Fabricius employed it for a well-known group of insects. 



Y 2 



