BIBLIOGRAPHIC LIST OF GENERA AND SPECIES. 459 



DISCOPHTCUS Walcott. Genotype: D. typicale Walcott, 



Discophycus Walcott, Trana. Albany Inst., 10, 1883, p. 19 (adv. sheets, 1879). — 

 Miller, N. A. Geol. Pal., 1889, p. 117. 



Discophycus typicale Walcott. 



Discophycus typicalis Walcott, Trans, Albany Inst., 10, 1883, p. 19, pi. 2, figs. 



18, 18a (adv. sheets, 1879). — James, Jour. Cincinnati Soc. Nat. Hist., 7, 



1884, p. 128, pi. 5, fig. 4. 

 Utica: Trenton, Oneida County, New York. 



DISCOPHTLLUM Hall. Genotype: D. peltatum Ilall. 



Discophyllum Hall, Pal. New York, 1, 1847, p. 277 



Discopliyllum peltatum Hall. 



Discophyllum peltatum Hall, Pal. New York, 1, 1847, p. 277, pi. 75, fig. 3. 

 Chazyan (Normanskill) or Trenton (Snake Hill): Near Troy, New York. 



DISCOSORUS Hall. Genotype: D. conoideus Hall 



Discosorus Hall, Pal. New York, 2, 1852, p. 99, pi. 28.— Woodward, Mpn. Mol- 

 lusca, pt. 3, 1856, p. 449.— Hall, 12th Rep. New York State Cab. Nat. Hist., 

 1859, p. 81.— Hyatt, Proc. Boston Soc. Nat. Hist., 22, 1883, p. 272.— Foord, 

 Cat. Foss. Ceph. British Mus., 1, 1888, p. 194.— Miller, N. A. Geol. Pal., 1889, 

 p. 436. 



Discosorus conoideus Hall. 



Columns of circular discs, etc., Bigsby, Trans. Geol. Soc. London, ser. 2, 1, 1824, 

 p. 204, pi. 30, figs. 4, 6. 



Discosorus conoideus Hall, Geol. Lake Sup. Land Dist., Foster and Whitney's 

 Rep., 1851, p. 222, pi. 34, figs. 2, 3; Pal. New York, 2, 1852, p. 99, pi. 28, 

 figs. 13a-c.— WTiitfield, Geol. Wisconsin, 4, 1882, p. 299, pi. 20, fig. 6.— 

 Foord, Cat. Foss. Ceph. British Mus., 1, 1888, p. 196, fig. 25. 



Orthoceras? (Discosorus) conoideus Barrande, Syst. Sil. du Centre Boheme, 2, 

 pt. 3, 1864, p. 750, pi. 232, 437, 474.— Foerste, Proc. Boston Soc. Nat. Hist., 

 24, 1889, p. 286; Geol. Surv. Ohio, Pal., 7, 1893, p. 546, pi. 36, fig. 8. 



Gomphoceras conoideum Whitfield and Hovey, Bull. Amer. Mus. Nat. Hist., 11, 

 pt. 2, 1899, p. 172. (Regarded as internal cast of siphon.) 



Silurian: Ontario and Lockport, New York (Lower Clinton); Todds Fork, Clin- 

 ton County, Ohio (Brassfield); Ashford, etc., Wisconsin; Drummond Island, 

 Lake Huron (Niagaran). 



Discosorus gracilis Foord. 



Discosorus BaiTande, Syst. Sil. Boheme, 2, suppl. 1877, pi. 474, figs. 9, 10. 



Discosorus gracilis Foord, Cat. Foss. Ceph. British Mus., 1, 1888, p. 198, fig. 26. 

 Niagaran: Drummond Island, Lake Huron. 



Discosorus remotus Foord. 



Columns of circular discs, etc., Bigsby, Trans. Geol. Soc, 2d ser., 1, 1824, p. 204, 



pi. 30, fig. 7. 

 Discosorus remotus Foord, Cat. Foss. Ceph, British Mus., 1, 1888, p. 197. 

 Niagaran: Drummond Island, Lake Huron. 



DISCOTRYPA Ulrich. Genotype: Chaetetes elegans Ulrich. 



Discotrypa Ulrich, Jour. Cincinnati Soc. Nat. Hist., 5, 1882, p. 155. — Miller, N. 

 A. Geol. Pal., 1889, p. 300.— Ulrich, Geol. Surv. Illinois, 8, 1890, p. 378.— 

 Nicklesand Bassler, Bull. U. S. Geol. Surv., 173, 1900, p. 30. 



