882 BULLETIN 92, UNITED STATES NATIONAL MUSEUM. 



ORBICULA PARMULATA Hall. See Orbiculoidea parmulata. 

 ORBICULA PRIMA Owen. See Obolus matinalis. 

 ORBICULA? SQUAMIFORMIS Hall. See Pholidops squamiformis. 

 ORBICULA? SUBTRUNCATA Hall. See Pholidops subtruncata. 

 ORBICULA TENUILAMELLATA Hall. See Schizotreta tenuilamellata. 

 ORBICULA TERMINALS Emmons. See Trematis terminalis. 

 ORBICULA TRUNCATA Emmons. See Orbiculoidea lamellosa. 



ORBICULOIDEA D'Orbigny. Genotype: Orbicula morrisi Davidson. 



Orbiculoidea D'Orbigny, Compt. Rend, de 1'Acad. Sci., 25, 1847, p. 269; Pro- 

 dromede Pal., 1, 1850, p. 44. Davidson, British Foss. Brach., Pal. Soc., 1853, 

 p. 129? Emmons, Amer. Geology, 1, pt. 2, 1855, p. 200. Pictet, Traite de 

 Pal., 2d ed., 4, 1857, p. 70. Davidson, Mon. British Sil. Brach. Pal. Soc., 

 1866, p. 72. Dall, Bull. Mus. Comp. Zool., 3, 1871, p. 37; Amer. Journ. 

 Conch., 7, 1871, p. 74. Zittel, Handb. Pal., 1, 1880, p. 667. Herrick, Bull. 

 Sci. Lab. Denison Univ., 4, 1888, p. 12. Miller, N. A. Geol. Pal., 1889, p. 

 356. Hall and Clarke, Pal. New York, 8, pt. 1, 1892, p. 125, fig. 64; p. 128, 

 fig. 160; pp. 160, 168. Beecher, Amer. Jour. Sci., 3d ser., 44, 1892, p. 148. 

 Winchell and Schuchert, Geol. Minnesota, 3, 1893, p. 363. Beecher, Amer. 

 Nat., 27, 1893, p. 600. Hall and Clarke, llth Ann. Rep. New York State Geol., 

 1894, p. 256. Koken, Die Leitfossilien, Leipzig, 1896, p. 230, fig. 189, 3, 4. 

 Miller, N. A. Geol. Pal., 2d App., 1897, p. 761 Grabau, Bull. Buffalo Soc. 

 Nat. Sc., 6, 1899, p. 183. Grabau and Shimer, N. A. Index Fossils, 1, 1907, 

 p. 204. Schuchert, Zittel-Eastman Textb. Pal., 1900, p. 310; ibid., 2d ed., 

 1913, p. 377. 



Discina Hall (not Lamarck), Pal. New York, 3, 1859, p. 159; 16th Rep. New York 

 State Cab. Nat. Hist., 1863, p. 130; 1867, p. 15. 



ORBICULOIDEA CONICA Dwight. See Schizotreta conica. 

 ORBICULOIDEA FLLOSA Emmons. See Schizocrania filosa. 



Orbiculoidea harti Clarke. 



Orbiculoidea Hartii Clarke, Arch. Mus. Nac. Rio de Janeiro, 10, author's Engl. ed., 



1900, p. 7, pi. 1, figs. 5, 6. 

 Silurian: Rio Trombetas, Brazil. 



Orbiculoidea lamellosa (Hall). 



Orbicula lamellosa Hall (not Broderip, 1833), Pal. New York, 1, 1847, p. 99, pi. 30, 

 fig. 10. 



Orbiculoidea lamellosa Hall and Clarke, Pal. New York, 8, pt. 1, 1892, pi. 4E, 

 fig. 12. Winchell and Schuchert, Geol. Minnesota, 3, 1893, p. 364, pi. 29, 

 fig. 25. Schuchert, Bull. U. S. Geol. Surv., 87, 1897, p. 279. Weller, Geol. 

 Surv. New Jersey, Pal. 3, 1903, p. 147, pi. 9, figs. 1, 2. Grabau and Shimer, 

 N. A. Index Fossils, 1, 1907, p. 204. 



Discina lamellosa Hitchcock, Geol. Vermont, 1, for 1861, 1862, p. 293, fig. 197. 



Orbicula truncata Emmons, Amer. Geology, 3, 1855, p. 200, fig. 62. 



Discinia truncata Emmons, Manual Geol., 1860, p. 99. 



Discina circe Billings, Geol. Surv. Canada, Pal. Foss., 1, 1863, p. 51, fig. 55. 

 Miller, N. A. Geol. Pal., 1889, p. 344, fig. 561. Lesley, Geol. Surv. Pennsyl- 

 vania, Rep. P 4, 1889, p. 209, fig. Billings, Geol. Canada, 1863, p. 159, fig. 

 125. 



