848 BULLETIN 92, UNITED STATES NATIONAL MUSEUM. 



NAUTILUS TYRANS Billings. See Plectoceras tyrans. 

 NAUTILUS VERSUTUS Billings. See Litoceras versutum. 



Nebulipora McCoy. Genotype: N. papillata McCoy. 



Nebulipora McCoy, Ann. Mag. Nat. Hist., 2d ser., 6, 1850, p. 282; British Pal. 



Foss., 1852, p. 22; Cont. British Pal., 1854, p. 168. Salter, Cat. Camb. Sil. 



Foss., 1873, p. 108. Ulrich, Jour. Cincinnati Soc. Nat. Hist., 5 1882, p. 155. 



Miller, N. A. Geol. Pal., 1889, p. 198. 



Observation. Nothing has been added to McCoy's original descriptions. The 

 genus, apparently monticuliporoid in its structure, not having been characterized 

 with the precision necessary for modern purposes, has not been used by recent 

 writers. 



Nelimenia Castelnau. Genotype: N. incognita Castelnau. 



Nelimenia Castelnau, Essai Syst. Sil. 1'Amerique Septent., 1843, p. 33. 



Observation. Not recognized. Based probably upon a fragment of Phragmo- 

 ceras or Oncoceras. 



Nelimenia incognita Castelnau. Not recognized. 



Nelimenia incognita Castelnau, Essai Syst. Sil. 1'Amerique Septent., 1843, p. 33, 



pi. 10, fig. 4. 



Ordovician: Falls of Montmorency Kiver, Canada. 

 Observation. Probably the same as Oncoceras constrictum Hall. 



NEMAGRAPSUS CAPILLARIS Emmons. See Thamnograptus capillaris. 

 NEMAGRAPSUS ELEGANS Emmons. See Nemagraptus gracilis. 



NEMAGRAPTUS Emmons. Genotype: N. elegans Emmons. 



Nemagrapsus Emmons, Amer. Geology, 1, pt 2, 1855, p. 109. 



Nemagraptus Hall, Pal. New York, 3, 1859, p. 511, footnote; 13th Rep. New York 

 State Cab. Nat. Hist., 1860, p. 56, footnote. Zittel, Handb. Pal., 1, 1879, p. 

 298. Miller, N. A. Geol. Pal., 1889, p. 198. Wiman, Bull. Geol. Inst. Univ. 

 Upsala, 2, pt. 2, 1896, p. 266. Elles and Wood, Mon. British Grapt., Pal. Soc., 

 1903, pp. xxxviii, 125. Ruedemann, Mem. New York State Mus., 11, pt. 2, 

 1908, p. 274; Zittel-Eastman Textb. Pal., 2d ed., 1913, p. 130. 



Crenograptus Hall, 20th Rep. New York State Cab. Nat. Hist., 1868, footnote, p. 179, 

 pp. 217, 236; rev. ed., 1870, p. 251. Nicholson, Mon. British Grapt., 1872, 

 p. 112. Zittel, Handb. Pal., 1, 1879, p. 298. Tullberg, Sveriges Geol. 

 Unders., sec. C, No. 55, 1883, p. 12. Miller, N. A. Geol. Pal., 1st App., 1892, 

 p. 668. Wiman, Bull. Geol. Inst. Univ. Upsala, 2, pt. 2, 1896, p. 266 

 Koken, Die Leitfossilien, Leipzig, 1896, p. 328. Walther, Zeits d. d. geol. 

 Gesell., 49, 1897, p. 251. Roemer and Freeh, Leth. geog., 1 Theil, Leth. 

 Pal., 1, 3 Lief., 1897, p. 584. Grabau and Shimer, N. A. Index Fossils, 1, 

 1906, p. 28. (Genotype: Graptolithus gracilis Hall.) 



Helicograpsus Nicholson, Ann. Mag. Nat. Hist., 4th Her., 2, 1868, p. 23. (Geno- 

 type: G. gracilis Hall.) 



Stephanograptus Geinitz, Neues Jahrb. Min., etc., 1866, p. 124. (Genotype: G. 

 gracilis Hall.) 



Nemagraptus exilis (Lapworth). 



Ccenograptus exilis Lapworth, MS. Rep., 1890. 



Stephanograptus exilis (Lapworth) Gurley, Jour. Geol., 4, 1896, p. 68, 101. 



Nemagraptus exilis Ruedemann, Mem. New York State Mus., 11, pt. 2, 1908, pp. 



287-290, pi. 17, figs. 3, 5, 8, 9, figs. 202, 203. 

 Chazyan (Normanskill): Glenmont and Stockport, New York. 

 Plesiotypes.Czt. No. 54250, U.S.N.M. 



