344 



BRACHIOPODA. 



[nis. 



canadensis, Billings, 1857, (Obolus cana- 

 densis,) Rep. of Progr. Geo. Sur. of 

 Can., p. 189, and Can. Nat., vol. 6, p. 

 222, Black Riv. Gr. 



conradi, Hall, 1868, (Obolus conradi,) 20th 

 Rep. N. Y. St. Mus. Nat. Hist., p. 368, 

 Niagara Gr. 



galtensis, see Trimerella galtensis. 



magnificus, Billings, 1872, (Obolellina 

 magnifica,) Canadian Naturalist, vol. 6, 

 p. 330, Black Riv. Gr. 



parvus, Whitfield, 1882, Geo. Wis., vol. 4, 



p. 347, Galena Gr. 



DISCINA, Lamarck, 1819, Hist. Nat. Anim. 

 sans Vert., vol. 6, p. 236. [Ety. discus, 

 a flat, round plate ; the termination 

 inus, implying resemblance.] Circular, 

 longitudinally or transversely oval ; 

 dorsal valve conical, with apex inclined 

 toward the posterior margin; ventral 

 valve opercular, 



flat, or partly 



convex, perfo- 

 rated by a nar- 

 row, oval, longi- 

 tudinal slit, 



reaching to near 

 the posterior 



margin, and 

 i * . 



FIG. 559,-Discina ostre- 

 oides. 



placed in the 



middle of an oval depressed disk ; sur- 

 face smooth, striated 



from the apex to the \. '. 



margin, or having con- 

 centric lines of growth 



produced in foliaceous 



expansions; structure 



horny, and perforated 



by minute tubuli. Type 



D. ostreoides. 

 acadica, see Stenotheca 



acadica. 

 alleghania, Hall, 1860, 



13th Rep. N. Y. St. Mus. 



Nat. Hist., p. 77, and 



Pal. N. Y., vol. 4, p. 25, 



Chemung Gr. 

 ampla, Hall, 1867, Pal. 



N. Y., vol. 4, p. 17, 



Oriskanv sandstone FIG. 561. Discina ostreoides, 2diam. u, 

 iauusujue. r<( ante rior adductors ; 6, posterior add 

 *' ing muscles ; ?, retractor muscles. 



convexa, Shumard, 1858, Trans. St. Louis 



Acad. Sci., vol. 1, p. 221, Coal Meas. 

 discus, Hall, 1859, Pal. N. Y., vol. 3, p. 



159, Low. Held. Gr. 

 doria, Hall, 1863, 16th Rep. N. Y. St. Mus. 



Nat. Hist,, p. 26, Ham. Gr. 

 elmira, Hall, 1863, 16th Rep. N. Y. St. 



Mus. Nat. Hist., p. 29, Chemung. Gr. 

 gallaheri, Winchell, 1865, Proc. Acad. 



Nat. Sci., p. 112, Marshall Gr. 

 grandis, Vanuxem, 1842, Geo. Rep. 3d 



Dist. N. Y., p. 152, and Pal. N. Y., vol. 



4, p. 17, Cornif. and Ham. Gr. 

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



The name was preoccupied. See D. 



ampla. 

 humilis, Hall, 1863, 16th Rep. N. Y. St. 



Mus. Nat. Hist., p. 25, Marcellus Slate 



and Ham. Gr. 

 inutilis, Hall, 1863, 16th Rep. N. Y. St. 



Mus. Nat. Hist,, p. 130, Potsdam Gr. 

 lamellosa, Hall, 1847, (Orbicula lamellosa.) 



The name was preoccupied by Broder- 



ick in 1833. Billings has described it 



as D. circe. 

 lodensis, Vanuxem, 1842, (Orbicula lo- 



densis,) Geo. Rep. 3d Dist. N. Y., p. 



168, and Pal. N. Y., vol. 4, p. 22, Gen- 



esee Slate, 

 manhattanensis, Meek and Hayden, 1859, 



Proc. Acad. Nat. Sci., p. 25, Coal Meas. 



Proposed instead 



grandis of Hall, 

 capax, White, 1862, Proc. Bost Soc. Nat. 



Hist., vol. 9, p. 30, Waverly or Marshall Gr. 

 capuliformis, McChesney, syn. for D. nitida. 

 circe, Billings, 1862, 



Pal. FOBS, vol. 1, p. 



51,TrentonGr. See 



remarks on D. la- 

 mellosa. 

 clara, Spencer, 1884, 



Bull. No. 1, Mus. 



Univ. St. Mo., p. 56, 



Niagara Gr. 

 c o n n a t a , Walcott, 



1885, Monogr. U.S. 



Geo. Sur., vol. 8, p. 214, Devonian, 

 conradi, Hall, 1859, Pal. N. Y., vol. 3, p. 



161, Low. Held. Gr. 



Umbo ; /, foramen ; d, disk ; 

 uctors; c, c, protractor slid- 



ViQ. 560.-Discina 

 circe. 



marginalis, Whitfield, 1880, Ann. Rep. 

 Geo. Sur. Wis., p. 70, and Geo. Wis., 

 vol. 4, p. 325, Ham. Gr. 



media, Hall, 1863, 16th Rep. N. Y. St. 

 Mus. Nat. Hist., p. 27, Ham. and Che- 

 mung Grs. 



meekana, Whitfield, 1882, Desc. New 

 Spec. Foss. from Ohio, p. 228, Coal Meas. 



microscopica, Shumard, 1861, Am. Jour. 

 Sci. and Arts, vol. 32, p. 213, Pots- 

 dam Gr. 



minuta, Hall, 1843, (Orbicula minuta,) 

 Geo. Rep. 4th Dist. N. Y., p. 180, and Pal. 

 N. Y., vol. 4, p. 16, Marcellus Shale. 



missourierws, Shumard, 1858, Trans. St. 

 Louis Acad. Sci., Coal Meas. Syn. for 

 D. nitida. 



