488 



LAMELLIBRANCHIA TA. 



[MAT. MEG. 



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



Garb, 

 delicatus, Meek & Worthen, 1870, Proc. 



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



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

 hamiltonise, Hall, 1870, Prelim. Notice 



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



5, pi. 51, figs. 1-10, Ham. Gr. 

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



Garb, 

 micronema, Meek & Worthen, 1866, Proc. 



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

 obsoletus, Meek, 1871, Reg. Rep. Univer- | 



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



p. 334, Coal Meas. 



FIG 846. Matherla 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. 

 Geo. p. 302, Carb. 



tennistriatus, Meek & Worthen, 1867, 

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

 Up. Coal Meas. 



truncatus, 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.] Eqnivalve, 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. 

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

 p. 343. [Ety. meyas. great; omos, 

 shoulder.] Large, equivalve, concen- 

 trically lined, longitudinal; umbones 

 anterior incurved; shell thick and 

 along the hinge-line thickened on the 

 interior; muscular imprt-ssion large 

 and deep, with two small circular 

 pits above. Type M. canadensis. 



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

 p. 343, Guelph Gr. 



compressus, Nicholson & Hinde, 1874, 



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



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



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

 >88 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. 



KiG. 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. 



cardiiformis, 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 cardiiformis. 



cordiformis, see Mytilarca cordiformis. 

 jamesi, see Ambonychia jamesi. 

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



p. 467, Oriskany sandstone, 

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



Low. Held. Gr. 



lyoni, syn. for Cardiopsis radiata. 

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



p. 276, Low. Held. Gr. 



