488 



LAMELLIBRANCHIA TA. 



[MAT. — MEG. 



curtus, Hartt, 1868, Acad. Geol., p. 302, 



Carb. 

 delicatus, Meek & Worthen, 1870, Proc. 



Acad. Nat. Sci., p. 40, and Geo. Sur. 



111., vol. 5, p. 575, Up. Coal Meas. 

 hamiltonia?, Hall, 1870, Prelim. Notice 



Lam. Shells, p. 13, and Pal. N. Y., vol. 



5, pi. 61. figs. 1-10, Ham. Gr. 

 hardingi, Hartt, 1868, Acad. Geol., p. 302, 



Carb. 

 micronema, Meek & Worthen, 1866, Proc. 



Acad. Nat. Sci., p. 261, Kaskaskia Gr. 

 obsoletns, Meek, 1871, Reg. Rep. Univer- 

 sity W. Va., p. 5, and Pal. Ohio, vol. 2, 



p. 334, Coal Meas. 



Matheria tener. 



ovatus, Hall, 1870, Prelim. Notice Lam. 

 Shells, p. 15, and Pal. N. Y., vol. 5, p. 

 351, Waverly Gr. 



parvus, White & Whitfield, 1862, Proc. 

 Bost. Soc. Nat. Hist., vol. 8, p. 299, 

 Kinderhook Gr. 



sangamonensis, Worthen, (in press,) Geo. 

 Sur. 111., vol. 8, p. 123 Coal Meas. 



shubenacadiensis, Hartt, 1868, Acad. 

 G* o. p. 302, Carb. 



tenuistriatus, Meek & Worthen, 1867, 

 Proc. Chi. Acad. Sci., vol. 1, p. 17, 

 Up. Coal Meas. 



truncal us, Walcott, 1885, Monogr. U. S. 

 Geo. Sur., vol. 8, p. 243, Carboniferous. 

 Matheria, Billings, 1858, Can. Nat. 

 and Geo., vol. 3, p. 440. [Ety. proper 

 name.] Equivalve, inequilateral ; 

 beaks anterior; two small, obtuse, 

 cardinal teeth in the left valve, and 

 one in the right ; no lateral teeth ; two 

 muscular impressions; ligament ex- 

 ternal. Type M. tener. 



tener, Billings, 1858, Can. Nat. and 

 Geo., vol. 3, p. 440, Trenton Gr. 

 Megalomus, Hall, 1852, Pal. N. Y., vol. 2, . 

 p. 343. [Ety. megas. great ; amos, 

 shoulder.] Large, equivalve, concen- 

 trically lined, longitudinal; umbones 

 anterior incurved; shell thick and 

 along the hinge-line thickened on the 

 interior; muscular impres^on large 

 and deep, with two small circular 

 pits above. Tvpe M. canadensis. 



canadensis, Hall, 1852, Pal. N. Y., vol. 2, 

 p. 343, Guel|>h Gr. 



comprtssus, Nicholson & Hinde, 1874, 

 Can. Jour., vol. 14, p. 159, Niagara Gr. 

 Megambonia. Hall, 1859, Pal. N. Y., vol. 3, 

 p. 273. [Ety. megas, great; ambon, the 

 boss of a shield.] Equivalve, inequi- 

 lateral, subovoid, gibbous in the middle 

 and toward the umbones ; anterior side 



lobed or auriculate ; muscular impres- 

 sion large; posterior cardinal margin 

 expanded or alate; hinge-line crenu- 

 lated anteriorly; teeth numerous; sur- 

 face concentrically lined, and sometimes 

 with radiating striae. Type M. subor- 

 bicularis. 



Fig. 847.— Megalomus canadensis. 



aviculoidea, Hall, 1859, Pal. N. Y., vol. 3, 



p. 274, Low. Held. Gr. 

 bellistriata, Hall, 1859, Pal. N. Y., vol. 3, 



p. 467, Oriskany sandstone, 

 cancellata, Hall, I860, Can. Nat. and Geo., 



vol. 5, p. 153, Up. Silurian, 

 eardiiformis, Hall, 1843, (Pterinea cardii- 



formis,) Geo. Rep. 4th Dist. N. Y., p. 



172, and Pal. N. Y., vol. 5, p. 515. Cor- 



nif. Gr. 



Fig. 848.— Megambonia eardiiformis. 



cordiformis, see Mytilarca cordiformis. 

 jamesi, see Ambonychia jamesi. 

 lamellosa, Hall, 1859, Pal. N. Y., vol. 3, 



p. 467, Oriskany sandstone, 

 lata, Hall, 1859, Pal. N. Y., vol. 3, p. 277, 



Low. Held. Gr. 

 lyord, syn. for Cardiopsis radiata. 

 mytiloi.lea, Hall, 1859, Pal. N. Y., vol. 3, 



p. 276, Low. Held. Gr. 





