436 BULLETIN 92, UNITED STATES NATIONAL MUSEUM. 



Didymograptus subtenuls Continued. 



Dicellograptus tenuis Lapworth, Roy. Soc. Canada Trans. 5, sec. 4, 1886, p. 178. 

 Leptograptus tenuis Lapworth, Roy. Soc. Canada Trans., 10, sec. 4, 1886, p. 183. 

 Leptograptus subtenuis Walcott, Bull. Geol. Soc. Amer., 1, 1890, p. 338. 

 Leptograpsus subtenuis Gurley, Jour. Geol., 4, 1896, p. 296 (gen. ref.). 

 Didymograptus tennis Ruedemann, Bull. New York State Mus., 42, 1901, p. 540f. 

 Didymograptus subtenuis Ruedemann, Mem. New York State Mus., 11, pt. 2, 



1908, pp. 253-255, pi. 14, figs. 1, 2, text figs. 160, 161. 

 Chazyan (Normanskill) : Kenwood, Mount Moreno, and Stockport, New York; 



Canada. 



Didymograptus superectes Lapworth. 



Didymograptus superectes Lapworth, Cat. West. Scot. Foss., pi. 3, fig. 74, 

 a, b; Proc. Belfast Field Club, 1877, p. 142, pi. 7, figs. 15a, b. Elles and 

 Wood, Mon. British. Grapt., Pal. Soc., pt. 1, 1901, p. 19, pi. 1, figs. 9a, b. 



Middle Ordovician: South Scotland (Glenkiln); Oklahoma (Xormanskill-String- 

 town). 



DIDYMOGRAPTUS TENUIS Ruedemann. See Didymograptus subtenuis. 

 DIDYMOGRAPTUS (GONIOGRAPTUS) THUREAUI McCoy. See Goniograptus thureaui. 



Didymograptus tornquisti Ruedemann. 



Didymograptus tornquisti Ruedemann, Mem. New York State Mus., 7, pt. 1, 



1904, p. 688, pi. 13, figs. 6, 7. 

 Canadian (Deepkill, Didymograptus bifidus zone): Deepkill, Rensselaer County, 



New York. 



DIDYMOPORA Ulrich. See Fistulipora McCoy. 



DIKELOCEPHALUS Owen. Genotype: D. minnesotensis Owen. 



Dikelocephalus Owen, Geol. Surv. Wisconsin, Iowa, Minnesota, 1852, p. 573. 

 Billings, Canadian Nat. Geol., 5, 1860, p. 306. Hall, 16th Ann. Rep. New 

 York State Cab. Nat. Hist., 1863, p. 137. Billings, Pal. Foss., 1, Geol. Surv. 

 Canada, 1865, p. 399. Chapman, Expos. Min., Geol. Canada, 1864, p. 137. 

 Salter, Mem. Geol. Surv. Great Britain, 3, 1866, p. 303. Hall, Trans. Albany 

 Inst., 5, 1867, p. 116. Hall and Whitfield, U. S. Geol. Surv. Expl. 40th Parl., 

 4, 1877, p. 225. Salter, Mem. Geol. Surv. Great Britain, 3, 2d ed., 1881, p. 

 497. Whitfield, Geol. Wisconsin, 4, 1882, p. 200. Zittel, Handb. Pal., 2, 

 1885, p. 596. Beecher, Amer. Jour. Sci., 4th ser., 3, 1897, p. 192; Zittel- 

 Eastman Textb. Pal., 1, 1900, p. 629. Raymond, ibid., 2d ed., 1913, p. 720. 



Dikellocephalus Dames, Richthofen's China, Berlin, 4, 1883, p. 5. Koken, Die 

 Leitfossilien, Leipzig, 1896, p. 17, fig. 10, fig. 8. 



Dicelocephalus Barrande, N. Jahrb. f. Min., 1853, p. 336. 



Dicellocephalus Whitfield, Ann. Rep. Wisconsin Geol. Surv., 1878, p. 63. 

 Miller, N. A. Geol. Pal., 1889, p. 543. Matthew, Trans. Royal Soc. Canada, 

 10, sec. 4, 1893, p. 10. Berkey, Amer. Geol., 21, 1898, p. 290. 



DIKELOCEPHALUS AFFINIS Billings. See Platycolpus afiinis. 

 DIKELOCEPHALUS BARABUENSIS Whitfield. See Platycolpus barabuensis. 

 DIKELOCEPHALUS BELLI Billings. See Anomocarella belli. 

 DIKELOCEPHALUS CORAX Billings. See Apatokephalus corax. 

 DIKELOCEPHALUS CRISTATUS Billings. See Conokephalina? cristatus. 

 DIKELOCEPHALUS DEVINEI Billings. See Ptychoparia? devinei. 



