CONOHIFERA. 
FAmMIty XV.—MAcrrip&,* 
Includes VAUGANELLA (p. 479), LuTRARIA (p. 479), Macrra 
(p. 477), GNATHODON (p. 478), HETEROCORDIA, ANATINELLA 
(p. 479), CARDILIA (p. 469), and 
PSEUDOCARDIUM, Gabb. 
Type, Cardium Gabbi, Remond. Miocene and Pliocene. 
California. 
Hiymology, pseudo, false, and cardium, a generic name. 
Shell thick, heavy, resembling Leevicardiwm externally; lga- 
ment internal; lunule cordate; left valve with a large carti- 
lage pit and a V-shaped tooth, which articulates in a cor- 
responding depression in the right valve; 2 lateral teeth in 
each yalye, very strong and prominent. 
Faminty XVITI.—Myaciwwz.t 
PoroMYA, Forbes, 1843 (see p. 491). 
Passing into the genus Mya. 
Example, P. granulata. 
Synonyms, Eucharis, Recluz; Embla, Lovén; Cumingia 
parthenopea, Tiberri (non Thetis, Sby.). 
Animal with unequal siphons, clothed with numerous fila- 
ments, foot narrow and slender. 
Shell sub-orbicular, sub-equivalve, and inequilateral, thin, 
transparent, slightly nacreous within; valves closed, surface 
granulated ; teeth, in right valve, a short but strong cardinal, 
and in the left a minute triangular cardinal and a ridge-like 
Jateral on the posterior side. 
Distribution, 10 species. Britain, Scandinavia, Mediterranean, 
Tropical America. 
fossil, 13 species. Eocene. France, Germany, England, 
United States. 
CorsBuLomyA, Nyst, 1846 (see p. 490). 
Derivation, Corbula and Mya. 
Examples, Corbula complanata, Sowerby; ; Lentidium Medi- 
terraneum, Jan and Cristofori. 
Shell oval, transverse, depressed, closed, inequivalve, sub- 
inequilateral; right valve the larger, with one pyramidal tooth, 
* See p. 477. T See p. 489. 
7a 
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