374 BULLETIN 92, UNITED STATES NATIONAL MUSEUM. 



Cytherella? rugosa — Continued. 



Cytherella? rugosa Jones, Cent. Micro-Pal., Geol. Surv. Canada, pt. 3, 1891, p. S9 

 (gen. ref.).— Ulrich, Geol. IMinnesota, 3, pt. 2, 1894, p. 686, pi. 43, figs. 21-24.— 

 Grabau and Shimer, N. A. Index Fossils, 2, 1910, p. 366, fig. 1666, t, u. 



Black River (Leray) : Pauquette Rapids, Ottawa River, Canada. 



Trenton (Prosser) : Near Cannon Falls, Minnesota. 



Pledotypes.—Q&t. No. 41814, U.S.N.M. 



Cytherella? rugosa arcta Ulrich. 



Cytherella? rugosa var. arcta Ulrich, Geol. Minnesota, 3, pt. 2, 1894, p. 686, pi. 43, 



fig. 25. 

 Trenton (Prosser) : Near Cannon Falls, Minnesota. 

 Holotype.— Cat. No. 41815, U.S.N.M. 



Cytherella? subrotunda UHch. 



Cytherella? subrotunda Ulrich, Geol. Minnesota, 3, pt. 2, 1894, p. 685, pi. 44, 



fig. 43. 

 Black River (Decorah): Minneapolis, Minnesota. 



Cttherina alta Conrad. See Leperditia alta and L. jonesi. 



Cytherina balthica Hisinger (part). See Leperditia hisingeri. 



Cytherina crenulata Emmons. See Cytheropsis crenulata. 



Cytherina cylindrica Hall. See Leperditia cylindrica. 



Cytherina emmonsi Vogdes. See Cytheropsis emmonsi. 



Cytherina fabulites Conrad. See Leperditia fabulites. 



Cytherina phaseolus Hisinger. See Leperditia phaseolus. 



Cytherina spinosa Hall. See .^chmina spinosa. 



Cytherina subcylindrica Emmons. See Cytheropsis emmonsi. 



Cytherina subelliptica Emmons. See Cytheropsis subelUptica. 



CYTHERODON Hall. Genotype: C. nasutus Hall. 



Cytherodon Hall, 23d Rep. New York State Cab. Nat. Hist., 1873, pi. 14, figs. 

 19-21; Pal. New York, 5, pt. 1, Lam. 2, 1885, p. 53.— Miller, N. A. Geol. Pal., 

 1889, p. 477. 



Cytherodon? placidus Billings. 



Cytherodon? placidus Billings, Pal. Foss., Geol. Su^\^ Canada, 2, pt. 1, 1874, 



p. 137, pi. 8, fig. 10 (var. pi. 8, fig. 11). 

 Silurian: Arisaig, Nova Scotia. 



Cytherodon? soclalis Billings. 



Cytherodon? socialis Billings, Pal. Foss., Geol. Surv. Canada, 2, pt. 1, 1874, p. 138, 



pl.8, fig. 12. 

 Silurian; Arisaig, Nova Scotia. 



CYTHEROPSIS McCoy. Genotype: C. aldensis McCoy. 



Cytheropsis McCoy, Ann. Mag. Nat. Hist., 2d ser., 4, 1849, p. 414; Cont. BritishPal., 

 1854, p. 153; Synopsis British. Pal. Rocks., 1855, pi. 1 L, fig. 2.— Jones, Ann. 

 Mag. Nat. Hist. (3), 1, 1858, p. 248; Geol. Surv. Canada, dec. 3, 1858, p. 98.— 

 Barrande, Syst. Sil. du Centre Boheme, 1, Suppl., 1872, p. 508.— Miller, 

 N. A. Geol. Pal., 1889, p. 541. 



