306 MANUAL or THE MOLLUSCA. 



Stib-genus, &rateloupia, Desm. G-. in*egularis, PI. XX. fig. 11. 



Shell sub-equilateral, rounded in front, attenuated behind ; hinge with 1 

 anterior tooth, 3 cardinal teeth and several small posterior teeth; paUial 

 sinus deep, oblique. Fossil, 4< s-p. Eocene — Miocene. U. States, France. 



Aetemis, Poli. 



Mym. Artemis, in Greek myth. Diana. 



Ti/pe, A. exoleta, PL XX. fig. 12. {Syn. Dosinia, Scopoli.) 



Shell orbicular, compressed, concentrically striated, pale ; ligament sunk ; 

 lunule deep ; hinge like CtjUierea ; margins even ; pallial sinus deep, angular, 

 ascending. 



Animal with a large hatchet-shaped foot, projecting fi'om the ventral 

 margin of the shell ; mantle-margins slightly plaited ; siphons united to their 

 ends ; orifices simple ; palpi narrow. 



Bistr. 85 sp. Boreal — Tropical seas ; low-water — 80 fms. 



Fossil, 8 sp. Miocene — . U. States, Em-ope, S. India. 



Stib-genera. Cyclina, Desh. V, Sinensis, Chemn. Orbicular, ventricose, 

 margins crenulated, no lunule, sinus deep and angular. Bistr. 10 sp. 

 Seuegal, India, China, Japan. W. America. Fossil, 1 sp. Miocene, Bor- 

 deaux. 



dementia (papyracea) Gray. Thin, oval, white; ligament semi-internal; 

 posterior teeth bifid, sinus deep and angular. Animal with long, united 

 siphons, aud a large crescentic foot, similar to Artemis. Distr. 3 sp. 

 Australia, Philippines. 



LuciNOPSis, Forbes. 



Syn. Dosinia, Gray, 1847 (not Scop.) Mysia, Gray, 1851 (not Leach). 

 Cyclina, Gray, 1853 (not Desh.) 



Type, Venus undata, Pennant, PI. XX. fig. 13. {Lucina, and apsis, like.) 



Shell lenticular, rather thin ; right valve with 2 laminar, diverging teeth, 

 left with 3 teeth, the central bifid : muscular impressions oval, polished ; 

 pallial sinus very deep, ascending. 



Animal with mantle-margins plain; pedal opening contracted; foot 

 pointed, basal ; siphons longer than the shell, separate, divergent, with fringed 

 orifices. (Clark.) 



Distr. 1 sp. Norway, Brit. Fossil, 3 sp. Miocene. Brit. Belgium. 



Tapes, Miihlfeldt. 

 Syn. Paphia, Bolten, 1798. Pullastra, G. Sby. 

 Example, T. pullastra, PL XX. fig. 14. {Tapes, tapestry.) 

 Shell oblong, umbones anterior, margins smooth ; teeth 3 in each valve, 

 more or less bifid; pallial sinus deep, rounded. 



Animal spinning a byssus ; foot thick, lanceolate, grooved ; mantle plain 



