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 Or. 

 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 



Via. 559- Discina ostre- the posterior 



otdes. margin, and 



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. 



^N°.\. Ha vo'l. l 4 8 , 67 p. P ^ 



Oriskany sandstone! FlQ 561— Discina ostreoides, 2diam. u, Umbo;/, foramen ; d, disk ; 

 T>rr\r\naaA ;,,c«,....l ^*T* °> anterior adductors ; 6, posterior adductors ; c, c, protractor si id- 

 i-roposea instead 01 V. ing muscles; r, retractor muscles, 

 grandis of Hall. 



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. <ir. 

 gallaheri, Winchefl, 1865, Proc. Acad. 



Nat. Sci., p. 112, Marshall (Jr. 

 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 (Jr. 

 lamellota, Hall, 1847, (Orbicula lamelloea.) 



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, Qofe> 



esee Slate, 

 manhattanensis. Meek and Hayden, 1859, 



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



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



Hist.,vol.9,p.30,WaverlyorMarshallGr. 

 capuliformis, McChesney, syn. for D. nitida. 

 circe, Billings, 1862, 



Pal. Foes, vol. 1, p. 



51, Trenton Gr. 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. 



Kig. 660.— Discina 

 circe. 



marginalis, Whitfield, 1880, Ann. Rep. 

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

 vol. 4, p. 325, Ham. (ir. 



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

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

 mung Grs. 



meekana, Whitfield, 1882, Desc. New 

 Spec. Fo88. 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. 



missourienm, Shumard, 1858, Trans. St. 

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

 D. nitida. 



