498 MANUAL OF THE MOLLUSCA. 
? CARDIOMORPHA, Koninck. 
Type, ©. oblonga (Isocardia), Sowerby (not Koninck). Car- 
bonate of lime. 
Shell Isocardia-shaped, smooth or concentrically furrowed, 
umbones 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. 
EDMONDIA, KONINCK. 
Example, K. sulcata, Ph. (T. Pal. Soc. 1850, Pl. XX., Fig. 5.) 
Carb. Britain. 
_ Synonyms, Allorisma, King (part). Sanguinolites, M‘Coy 
(part). 
Shell oblong, equiysive, thin, concentrically striated, close; 
umbones anterior; ligamental grooves narrow, external; 
hinge-line thin, edentulous, furnished with large oblique 
cartilage plates, placed beneath the umbones, 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, Ryckholt, 1856. Carb. Tournay. Shell 
like Hdmondia, with a single cardinal tooth in each valve. 
Lyons14, Turton, 1822 (not R. Brown). 
Synonyms, Magdala, Leach, 1827. Myatella, Brown. Pan- 
dorina, Scacchi. 
Type, Li. Norvegica, Pl. XXITI., Fig. 10. 
Shell nearly equivalve, left valve largest, thin, sub-nacreous, 
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. 
L. Norvegica ranges from Norway to the sea of Ochotsk; in 
15—80 fathoms. 
