PI.E.] 



LAMELLIBRANCHIA TA. 



503 



Species are left here for want of ma- 

 terial to determine their generic rela- 

 tions. 



carbonaria, Meek & 

 Worthen, 1866, 

 Proc. Chi. Acad. 

 Sci., vol. 1, p. 13, 

 Up. Coal Meas. 

 recticardinalis,Meek, 

 1875, Ohio Pal., 

 vol. 2. p. 331, Coal 

 Meas. 



FIG. 894. Placunopsls PLETHOMYTILUS, Hall, 

 In- 1883, Pal. N. Y., 

 vol. 5, pt. 1, p. 4. 

 (Plates and Ex- 

 planations.) (Ety. pletho, to be full; 

 Mytilus, a genus.] Mytilpid, gibbous ; 

 ligamental area finely striated ; no car- 

 dinal teeth ; lateral teeth small, oblique; 

 test, with concentric striae; differs from 

 Mytilacra in its true hinge-line and the 

 absence of teeth. Type P. ponderosus. 



recticardinalls. 

 ternal cast ot left 

 valve. 



FIG. 895. Plethomytilus pouderosus. 



arenaceus, Hall, 1870, (Mytilarca arena- 



cea,) Prelim. Notice Lam. Shells, p. 



20, and Pal. N. Y., vol. 5, pt. 1, p. 253, 



Schoharie grit, 

 knappi, Hall, 1884, Pal. N. Y., vol. 5, pt. 



1, p. 256, Ham. Gr. 

 mytilimeris, Conrad, 1842, (Inoceramus 



mytilimeris,) Jour. Acad. Nat. Sci., 



vol. 8, p. 246, Low. Held. Gr. 



oviformis, Conrad, 1842, (Inoceramus 

 oviformis,) Jour. Acad. Nat. Sci., vol. 

 8, p. 246, and Pal. N. Y., vol. 5, pt. 1, 

 p. 255, Ham. Gr. 



ponderosus, Hall, 1870, (Mytilarca pon- 

 derosa,) Prelim. Notice Lam. Shells, p. 

 21, and Pal. N. Y., vol. 5, pt. 1, p. 254, 

 Up. Held. Gr. 



PLEUROPHORUS, King, 1844, Ann. Mag. Nat. 

 Hist., vol. 14, p. 313. [Ety. pleuron, a 

 rib; phoros, bearing.] Inequilateral, 

 longitudinally oblong or subovate ; two 

 cardinal teeth in each valve, alternately 

 interlocking and divergent; one pos- 

 terior lateral tooth in each valve, the 

 receiving tooth in the left valve ; an- 

 terior adductor scar deep, and bounded 

 posteriorly by a ridge ; pallial line sim- 

 ple. Type P. costatus. 



angulatus, Meek & Worthen, 1865, Proc. 

 Acad. Nat. Sci. Phil., p. 247, and Geo. 

 Sur. 111., vol. 6, p. 529, Coal Meas. 



calhouni, Meek & Hayden, 1858, (Ed- 

 monia calhouni,) Trans. Alb. Inst., vol. 

 4, p. 80, and Pal. Up. Mo., p. 62, Per- 

 mian Gr. 



chesterensis, Worthen, 1884, Bull. No. 2, 

 111. St. Mus. Nat. Hist., p. 16, and Geo. 

 Sur. 111., vol. 8, p. 123, Kaskaskia Gr. 



costatiformis, Meek & Worthen, 1865. 

 Proc. Acad. Nat. Sci. Phil., p. 247, and 

 Geo. Sur. 111., vol. 3, p. 535, Keokuk Gr. 



meeki, Walcott, 1885, Monogr. U. S. Geo. 

 Sur., vol. 8, p. 246, Carboniferous. 



minimus, Worthen, 1884, Bull. No. 2, 111. 

 St. Mus. Nat. Hist., p. 17, and Geo. Sur. 

 111., vol. 8, p. 124, St. Louis Gr. 



monroensis, Worthen, 1884, Bull. No. 2, 

 111. St. Mus. Nat. Hist., p. 17, and Geo. 

 Sur. 111., vol. 8, p. 125, St. Louis Gr. 



oblongus, Meek, 1872, Pal. E. Neb., p. 212, 



occidentalis, Meek & Hayden, 1862, Trans. 



Alb. Inst., vol. 4, p. "80, and Pal. Up. 



Mo., p. 35, Coal Meas. 

 pallasi, as identified by Geinitz, is P. 



oblongus. 

 permianus, Swallow, 



1858, Trans. St. / 



Louis Acad. Sci., ( 1 



vol. 1, p. 192, Per- \ " 



mian Gr. 



quadricostatus,Daw- __ 



- S IG. 896. Pleurophorus 



boniferous. 

 simplus, as identified by Geinitz, is P. 



subcuneatus. 

 subcostatus, Meek & Worthen, 1865, Proc. 



Acad. Nat. Sci. Phil., p. 246, and Geo. 



Sur. 111., vol. 2, p. 347, Up. Coal Meas. 

 subcuneatus, Meek & Hayden, 1858, 



Trans. Alb. Inst., vol. 4, p. 81, and Pal. 



Up. Mo., p. 61, Permian Gr. 

 (?) subellipticus, Meek, 1867, Am. Jour. 



Sci., vol. 44, p. 181, and Pal. E. Neb., 



p. 211, Coal Meas. 

 tropidophorus, Meek, 1875, Ohio Pal., vol. 



2, p. 338, Coal Meas. 



