North American Palaeozoic Crustacea. 13 



Cyclus, De Koninck, 1841 ; M^m. Acad. Sci. Bruxelles, vol. 14, p. 18. 



The following description of the typical species, C, radialis, is given by 

 Dr. Woodward (Geol. Mag., vol. 7, 1870, No. 12, p. 557) :— " Carapace, 

 five lines long by four lines in breadth ; its general form is hemispheri- 

 cal, with a narrow smooth border (roundly indented behind, so as to 

 leave a rudimentary medial spine in the centre) ; the shield is divided 

 down its centre by a raised longitudinal (dorsal) ridge, from which 

 radiate 7 diverging ribs (transversely wrinkled), whose rounded ex- 

 tremities reach the lateral and posterior border." 



Americana, Packard, 1885 ; Am. Naturalist, vol. 19, p. 293. 



Coal Measures. 



Americana, Packard, 1886 ; Mem. Natl. Acad. Sci., vol. 3, p. 143, pi. 5, 

 figs. 1, 1 a ; pi. 6, figs. 4, 4 a. 

 Cythere, Mtiller, 1785 ; Entomostraca, p. 64. 



" Valves unequal, oblong-ovate to quadrate, smooth or rough, mostly 

 highest in front ; hinge with teeth and sockets at anterior and posterior 

 angles, variously developed." (Jones, Proc. Geol. Assoc, vol. 9, No. 7, 

 p. 19.) 



(Bei/richia) Americana, Shumard, 1858; Trans. Acad. Sci. St. Louis, 

 vol. 1, p. 227. Upper Coal Measures. 



carbonaria, Hall ; see Leperditia carbonaria. 



crassimarginata, Winchell, 1862 ; Proc. Acad. Nat. Sci. Phila., p. 429. 



Marshall. 



Cincinnatiensis, Meek, 1871 ; Proc. Acad. Nat. Sci. Phila., vol. 23, p. 331. 



Hudson River. 



Cincinnatiensis, Meek, 1873 ; see Entomis Cincinnatiensis. 



irregularis. Miller, 1878 ; Jour. Cincinnati Soc. Nat. Hist., vol. 1, p. 106, 

 pi. 3, figs. 7, 7 a. Hudson River. 



Nebrascensis, Geinitz, 1866 ; Carb. und Dyas in Nebraska, p. 2, pi. 1. fig. 2. 



Nebrascensis, Meek, 1872 ; Rept. U. S. Geol. Survey Territories, Final 

 Rept. Nebraska, p. 237, pi. 11, figs. 2, 3 a, b.? Coal Measures. 



Okeni; see Leperditia Okeni. 



Ohiones, Herrick, 1889; Bull. Den. Univ., vol. 4, p. 60, pi. 8, fig. 8; 

 vol. 3, pi. 3, fig. 19. Waverly. 



simplex. White & St. John, 1867 ; Prelim, notice new species Foss., p. 3. 



simplex. White & St. John, 1868 ; Trans. Chicago Acad. Sci., vol. 1, p. 127. 



St. Louis. 

 Cythere sp. ? Dawson, 1868 ; Acad. Geol., p. 256, fig. 78 a. Carboniferous. 



subUevis; see Leperditia snblavis. 



suhrecla; see Leperditia subj-ecta. 

 Cytherina, Lamarck, 1818 ; Animaux Sans Vert. vol. 5, p. 125. 



alta; see Leperditia alta. 



crenulata, Emmons, 1855 ; Am. Geology, vol. 1, p. 221, figs. 75 a, b, c, d. 



Trenton. 

 cylindrica ; see Isochilina cylindrica. 



Emmonsi, Vogdes, 1889 ; Annals N. Y. Acad. Sci., vol. v. No. 1 ; to replace 



C. subcylindrica, q. v. Trenton. 



spinosa ; see Beyrichia spinosa. 



