OLENELLUS AND OTHER GENERA OF MESONACID^ 26/ 



Genus ELLIPTOCEPHALA Emmons 



Elliptoccpliala Emmons, 1844, Taconic System, p. 21, legend of fig. i. 

 (Characterized.) 



ElUptocephala Emmons, 1846, Nat. Hist. New York, Agriculture, Vol. i, 

 pt. 5, p. 65, legend of fig. i. (Copy of preceding reference.) 



Olenus Hall. 1847, Nat. Hist. New York, Paleontolgy, Vol. i, p. 256, 

 footnote. (Places " Elliptocephalus" as a synonym of Olcmis.) 



EUptocephalus Emmons, 1849, Proc. American Assoc. Adv. Sci., First 

 meeting, p. 18. (Notes on the genus as distinct from Olenus and 

 Par ad oxides.) 



EUptocephalus Emmons, 1855, American Geology, Vol. i, pt. 2, pp. 114- 

 115. (Discussed.) 



EUptocephalus (Emmons), Marcou, i860, Proc. Boston Soc. Nat. Hist., 

 p. 371. (Considers "EUptocephalus" to be a true Paradoxides.) 



Olenellus (ElUptocephahis) Ford, 1877, American Journ. Sci., 3d sen, 

 Vol. 13. pp. 265-272. (A very full description of the type species O. 

 (E.) asaphotdes.) 



Olenelhis Ford, 1878, American Journ. Sci., 3d ser.. Vol. 15, p. 130, footnote. 

 (Discusses the generic relations of Olenellus, as represented by O. 

 asaphoides, and Paradoxides as represented by P. aciileatus and P. 

 kjeriM.) 



OlencUus Ford (in part), .1881, American Journ. Sci.. 3d ser., Vol. 22, pp. 

 250-259. (As discussed throughout the paper the genus Olenellus 

 includes forms now referred to ElUptocepliala. Mesonacis, and Ole- 

 nellus.) 



Olenellus Walcott (in part) [not Hall], 1886, Bull. U. S. Geol. Survey, 

 No. 30, pp. 162-166. (Described and discussed. As discussed the 

 genus includes forms now referred not only to Olenellus but to 

 ElUptocephala, CaUavia, and Peachella. On pages 622-623 are given 

 reasons for rejecting ElUptocephala as a generic name.) 



Olenellus Holm (in part), 1887, Geol. Foren. i Stockholm Forhandl, Bd. 9. 

 Hafte 7, p. 498-499. (Described in Swedish. As described and dis- 

 cussed throughout the paper this genus includes many of the forms 

 now placed in the family Mcsonacidae.) 



Ebenezeria Marcou, 1888, Mem. Boston Soc. Nat. Hist., Vol. 4, p. 123. 

 (Proposed as a new genus to replace " ElUptocephalus" because of 

 the similarity of the latter genus to ElUpsocephalus Zenker.) 



ElUptocephalus (Emmons), Marcou, 1890, American Geologist, Vol. 5. 

 p. 362. (Argues that "ElUptocephalus " has right of priority over 

 Olenellus.) 



Olenelius (Mesonacis) Walcott (in part), 1891, Tenth Ann. Rept. U. S. 

 Geol. Survey, p. 637. (Merely uses Mesonacis as a subgenus; the 

 forms referred to the subgenus are now placed with ElUptocephala and 

 Mesonacis.) 



ElUptocephala Cole, 1892, Natural Science, Vol. i, p. 340. (Discussed.) 



Mesonacis Peach and Horne (in part), 1892, Quart. Journ. Geol. Soc. 

 London, Vol. 48, p. 236. (As defined this genus includes forms now 

 referred to both EUiptocepliala and Mesonacis.) 



