CYC. — CYT.] 



CRUSTACEA. 



541 



Fig. 990.— Cyphas- 

 pis christyi. 



Cyclus americanw, Packard, 1885, Am. Nat., 

 vol. 19, p. 293, Coal Meas. Not de- 

 fined so as to be recognized. 

 Cyphaspis, Burmeister, 1843, Die Organ der 

 Trilobiten, p. 103. [Ety. cyplios, con- 

 vex; aspis, shield.] Cephalic shield 

 semicircular, posterior angles produced 

 in spines, margin thickened ; glabella 

 very convex, ovoid, no furrows, but 

 with two small pyriform basal lobes 

 bounded by deep furrows ; eyes small, 

 semilunate ; cheeks broad ; facial su- 

 tures proceed in a nearly straight line, 

 from the anterior margin to the eyes, and 

 are then directed to the posterior an- 

 gles ; thorax 10 to 17 segments, rounded 

 at their extremities ; axis tapering ; 

 pygidium small, axis short, lateral lobes 

 depressed. Type C. ceratopthalmus. 

 brevimarginatus, Walcott, 1885, Monogr. 

 U. S. Geo. Sur., vol. 

 8, p. 93, Trenton Gr. 

 christyi, Hall, Trans. Alb. 

 Inst., vol. 4, p. 188, Ni- 

 agara Gr. 

 coelebs, Hall, 1888, Pal. 

 N. Y., vol. 7, p. 151, 

 Low. Held. Gr. 

 craspedota, Hall, 1888, 

 Pal. N. Y., vol. 7, p. 

 148, Ham. Gr. 

 diadema, Hall, 1888, 

 Pal. N. Y., vol. 7, p. 

 144, Up. Held. Gr. 

 girardeauensis, Shumard, 1855, Geo. Rep. 



Mo., p. 197, Trenton Gr. 

 hybrida, Hall, 1888, Pal. 

 N. Y., vol. 7, p. 144, 

 Up. Held. Gr. 

 laevis, Hall, 1876, (Phil- 

 lipsia laevis,) Illust. 

 Devon. Foss., pi. 21, 

 Chemung Gr. 

 minuscula, Hall, 1876, 

 (Phillipsia minus- 

 cula,) Illust. Devon. 

 Foss., pi. 20, Up. Held. 

 Gr. 

 ornata, Hall, 1876, 



(Phillipsia ornata,) Fig. 991.— Cyphas- 

 Ulust. Devon. Foss. ^ girardeauen- 

 pl. 21, Ham. Gr. 

 ornata var. baccata, Hall, 1888, Pal. N. Y., 



vol. 7, p. 146, Ham. Gr. 

 stephanophora, Hall, 1888, Pal. N. Y., 

 vol. 7, p. 142, Up. Held. Gr. 

 Cythere, Muller, 1785, Entomostraca sue In- 

 secta, etc., p. 63. The type is C. fla- 

 vida a living species. The genus is un- 

 knowu in Palaeozoic rocks. 

 americana, see Beyrichia americana. 

 earbonaria, see Leperditia carbonaria. 

 cincinnatiensis, see Cytheropsis cincinnati- 



ensis. 

 crassimarginata, see Cytheropsis crassimar- 



ginata. 

 irregularis, see Cytheropsis irregularis. 

 nebraskensis, see Cytheropsis nebraskensis. 

 okeni, see Leperditia okeni. 



simplex, see Cytheropsis simplex. 



sublsevis, see Leperditia sublaevis. 



subrecta, see Leperditia subrecta. 

 Cytherella, inf lata. 

 I find in the 

 Acadian Geol- 

 ogy, p. 206, a 

 small Entomos- 

 traca, from the fig. 992.-Cythere]la in- 

 Coal Meas. of flata. 



Nova Scotia, fig- 

 ured under this name, but without 

 any description or reference to any 

 other author. The figures are repro- 

 duced. 

 Cytherella glandella, see Cytheropsis glan- 



della. 

 Cytherina, Lamarck, 1818, Anim. sans Vert. 

 t. v, p. 125. [Ety. diminutive of 

 Cythere.~\ A synonym for Cythere, 

 which is not a Palaeozoic genus. 



alta, see Leperditia alta. 



crenulata, see Cytheropsis crenulata. 



cylindrica, see Isochilina cylindrica. 



fabulites; see Leperditia fabulites. 



spinosa, see Beyrichia spinosa. Not Reuss 

 in 1844. 



subcylindrica, see Cytheropsis subcylin- 

 drica. 



subelliptica, see Cytheropsis subelliptica. 

 Cytheropsis, McCoy, 1849, Ann. and Mag. 

 Nat. Hist., 2d. ser., vol. 4, p. 249. [Ety. 

 Cytheropsis, resembling Cythere.] Dis- 

 tinguished from Cythere, which now 

 swarm in the sea, by the great thick- 

 ness of the valves, and in having eye 

 or muscle spots. Type C. aldensis. 



cincinnatiensis, Meek," 1872, (Cythere cin- 

 cinnatiensis,) Proc. Acad. Nat. Sci., p. 

 331, and Ohio Pal., vol. 

 1, p. 158, Hud. Riv. Gr. 



concinna, see Primitia 

 concinna. 



crassimarginata, Win- Fig. 993.— Cyther- 

 chell, 1862, (Cythere S cincin,mtl - 

 crassimarginata,) Proc. 

 Acad. Nat. Sci., p. 429, Marshall Gr. 



crenulata, Emmons, 1856, (Cytherina 

 crenulata,) Am. Geol., p. 220, Tren- 

 ton Gr. 



Fig. 994.— Cytheropsis glandella. 



glandella, Whitfield, 1882. (Cytherellina 

 glandella,) Bull. Am. Mus. Nat. Hist., 

 vol. 1, p. 94, Warsaw Gr. 



irregularis, S. A. Miller, 1878, (Cythere 

 irregularis,) Jour. Cin. Soc Nat," Hist., 

 vol. 1, p. 106, Hud. Riv. Gr. 



nebraskensis, Geinitz, 1866, (Cythere ne- 

 braskensis,) Carb. und Dyas in Neb., p. 

 2, Coal Meas. 



rugosa, Jones, 1858, Ann. Nat. Hist., 3d 

 ser., vol. 1, p. 249, Black Riv. Gr. 



siliqua, Jones, 1858, Ann. Nat. Hist., 3d 

 ser., vol. 1, p. 249, Black Riv. Gr. 



