608 SYSTEMATIC PALEONTOLOGY 



adductor and byssal scars of the left valve are not constant in the same 

 individual at all ages, and consequently that small differences of this kind 

 cannot safely be used as specific distinctions. The best character seems 

 to be the more minute surface sculpture when fully developed in normal 

 specimens." Dall, 1898. 1 



Ancestral forms of this genus have been recognized in rocks as ancient 

 as the Devonian. The recent species number about forty and are widely di- 

 tributed along the shores from low-water to one hundred fathoms. 



A. External surface not radially plicate. 



1. Outline sub-circular; concentric lamination, very close excepting 



in the umbonal region Anomia argentaria 



2. Outline transversely ovate; concentric lamination rather distant. 



Anomia tellinoides 



B. External surface radially plicate. 



1. Radial sculpture, lirate rather than cordate, primaries and second- 



aries not conspicuously differentiated Anomia ornata 



2. Radial sculpture cordate rather than lirate; primaries and second- 



aries conspicuously differentiated Anomia forteplicata 



ANOMIA AKGEXTARIA Morton 

 Plate XXXV, Figs. 1, 2 



Anomia argentaria Morton, 1833, Am. Jour. Sci., 1st ser., vol. xxiii, p. 



293, pi. v, fig. 10. 

 Anomia argentaria Morton, 1834, Syn. Org. Rem. Cret. Group, U. S., p. 61, 



pi. v, fig. 10. 

 Anomia argentaria Meek, 1864, Check List Inv. Fossils, N. A., Cret. and 



Jur., p. 6. 

 Anomia argentaria Conrad, 1868, Cook's Geol. Survey of New Jersey, p. 



724. 



Anomia argentaria Conrad, 1875, Kerr's Geol. of North Carolina, Appen- 

 dix A, p. 13. 



Anomia argentaria Gabb, 1876, Proc. Acad. Nat. Sci., Phila., p. 319. 

 Anomia argentaria Whitfield, 1885, Mon. U. S. Geol. Survey, vol. ix, p. 42, 



pi. iv, figs. 10, 11 (fig. 9 excluded). 



Anomia argentaria Johnson, 1905, Proc. Acad. Nat. Sci., Phila., p. 12. 

 f Anomia argentaria Bose, 1906, Bol. Inst. Geol. Mexico, No. 24, p. 38, pi. i, 



fig. 8. 

 Anomia argentaria Weller, 1907, Geol. Survey of New Jersey, Pal., vol. iv, 



p. 496, pi. liv, figs. 11-15. 

 ? " Anomia subtruncata " Bose, 1913, Bol. Inst. Geol. Mexico, No. 30, p. 41, 



pi. v, fig. 1. 



Description. " Thin, round, with numerous concentric strige."- 

 Morton, 1833. 



1 Trans. Wagner Free Inst. Sci., Phila., vol. iii, pt. iv, p. 781. 



