498 MANUAL OF THE MOLITISCA. 



? Caediomobpha, Koninck. 



Type, C. oblonga (Isocardia), Sowerby (not Xoninck). Car- 

 bonate of lime. 



Shell Isocardia-sbaped, smooth or concentrically fm-rowed, 

 nmbones prominent, hinge edentulous ; hinge-margin with a 

 narrow ligamental furrow, and an obscure internal cartilage 

 groove. 



Fossil, 38 species. Lower Silurian — Carb. North America, 

 Europe. 



Edmoindia, Koninck. 



Example, E. sulcata, Ph. (T. Pal. Soc. 1850, PI. XX., Fig. 5.) 

 Carb, Britain. 



Synonyms, AUorisma, King (part). Sanguinolites, M'Coy 

 (part). 



Shell oblong, equiys-lve, thin, concentrically striated, close ; 

 umbones anterior ; ligamental grooves narrow, external ; 

 hinge-line thin, edentulous, furnished with large oblique 

 cartilage plates, placed beneath the nmbones, and leaving space 

 for an ossicle ? or the plate may be equivalent to the sub-um- 

 bonal blade in Pholas ; pallial line simple ? 



Fossil, 4 species, Carb. — Permian. Europe. 



Sub-genus. Scaldia, Eyckholt, 1856. Carb. Tournay. Shell 

 like Edmondia, with a single cardinal tooth in each valve. 



Lyonsia, Turton, 1822 (not E. Brown). 



Synonyms, Magdala, Leach, 1827. Myatella, Brown. Pan- 

 dorina, Scacchi. 



Type, L. Norvegica, PL XXIII. , Fig. 10. 



Shell nearly equivalve, left valve largest, thin, sub-nacrcous, 

 close, truncated posteriorly ; cartilage plates oblique, covered 

 by an oblong ossicle ; pallial sinus obscure, angular. Struc- 

 ture intermediate between Pandora and Anatina ; outer layer 

 composed of definite polygonal cells. 



Animal with the mantle closed ; foot tongue-shaped, grooved, 

 byssiferous; siphons very short, united nearly throughout, 

 fringed ; lips large, palpi narrow, triangular. 



Distribution, 12 species. Greenland, North Sea, Norway, 

 "West Indies, Madeira, India, Borneo, Philippines, Peru. I 



L. Norvegica ranges from Norway to the sea of Ochotsk ; in 

 15—80 fathoms. 



