70<; 



CRUSTACEA. 



[BRO.- CYC 



of a median bay-like sulcus, constituting 

 two irregular, obliquely transverse 

 lobes, which converge downward and 

 meet near the middle of the ventral 

 region by a low, narrow, bent isthmus, 

 sinuous in tbe adult, but more or less 

 simply curved in the young state. The 

 dorsal portions of this horseshoe lobe 

 project outward ; there is a strong 

 semilunar ridge at each end of the 

 valve, parallel with the marginal 

 border, which has a slight outer rim. 

 Type B. uniHexa. 



bilobata, Jones, 1890, Quar. Jour. Geo. 

 Soc, vol. 46, p. 640, Uorniierous Gr. ; 

 and B. hindei, p. 510, Ham. Gr. ; and 

 B. semilunata, p. 648, Had. Riv. Gr. 



graniteni, I'lrieli, 1890, Jour. (in. Soc. 

 Nat. Hist , vol. 13, p. 205, 8r. l^ouis Gr. ; 

 and B. obesa, p. 189, Dp. Held, or Ham. 

 Gr. ; B.'persulcata and B. pumila, pp. 

 L16, 117, Hud. Kiv. Gr. 



lata, Vanuxem, 1842, (Agnostus latus,) 

 <ieo. Rep. N. Y., p. 80, and Pal. N. Y.. 

 vol. 2, p. 301, Clinton Gr. 



symmetrica, Hall, 1852, (Bevrichia sym- 

 metrica,) Pal. N. Y., vol. 2, p. 31 7," Ni- 

 agara I i 1 



ungula, (kypole, 1889, Am. Geo., vol. 4, 

 p. 338, Marcellus limestone. 

 Bbontzus senesceDs, Hall, 1802, 8th Ann. 



Rc'p. St. Geo. N. Y.. ( 'hemung Gr. 

 Bythocyi'kis. Brady, 1880, Rep. Ostracoda 

 of the Challenger, p. 45. [Ety. bu'hos, 

 the depth of the sea ; Cypris, a genus.] 

 Carapace smooth, more or less reni- 

 form ; left valve much larger than the 

 right, which it overlaps both on the 

 dorsal and ventral margins. 



devonica, B. indianensis, B. punctulata, 

 Ulrich, 1800, Jour. Cin. Soc. Nat. 

 Hist., vol. 13, p. 106, Up. Held, or 

 Ham. Gr. 



lindstromi and B. obtusa, Jones, 1800, 



Quar. Jour. Geo. Soc, vol. 46, p. 548, 



Anticosti Gr. 



( alymene has a subquadrate hypostoma, 



with two short spines posteriorly ; the 



• surface, when well preserved, isgranular 

 or tubercular. 



multicosta is from the Chazy Gr. 



vogdesi,Foerste, 1887, Bull. Denison Univ., 

 vol. 2, p. 05, Niagara Gr. 

 Cakcinosoma, Claypole, 18!>0, Am. Geo., 

 vol. 6, p. 400. [Ety. karkinos, a crab ; 

 soma, the body.] Proposed instead of 

 Eurysoma, on p. 250. Body ovate, 

 narrower in front, abruptly tapering 

 behind into a cylindrical abdomen 

 ending in a spiuiform tail ; head-shield 

 entire, roundly triangular, bluntly 

 pointed in front ; thoracic segments 6 

 or more, ending on each side in a 

 backwardly directed point ; abdominal 

 segments 4, subquadrate ; beyond these 

 is a sharply triangular spine ; appe nd- 

 ages consist of 5 pairs of organs, the 

 first 4 of which taper rapidly to a point 

 and are furnished with spinous pro- 



cesses; the swimming feet are thicker 

 and longer than the others, and con- 

 sist of three segments. Type G new- 

 lini, described at the same time on 

 p. 260, from the Waterlime I ir. 

 Ceratiocaris had numerous body- rings, 

 posterior to the bivalve carapace, car- 

 rying lamellar appendages, behind 

 which there was a pointed telson and 

 two lateral spines. 

 Conocoryphe is a synonym for Atops. 

 Ctbnobolbina, Ulrich, 1800, Jour. Cin. Soc. 

 Nat. Hist., vol. 13, p. 108. [Ety. kttnos, 

 comb; bolbos, bulb.] Carapace small, 

 elongate, suboval, strongly convex ; the 

 posterior two-fifths more or less bulb- 

 ous or subglobular, and separated from 

 the remainder by a deep, narrow sulcus, 

 extending in a gentle curve from the 

 dorsal margin more than half the dis- 

 tance across the valves toward the 

 postero- ventral border ; the anterior 

 three-fifths often with another oblique 

 but less impressed sulcus; valves 

 equal, dorsal margin straight, hinge 

 ' simple, veHtral edge thick, and the 

 true contact margins generally with a 

 row of small spines on each side ; in 

 a lateral view both are concealed by a 

 frill or flattened border, usually mis- 

 taken for the true contact edges ; surface 

 generally granulous. Type C. ciliata. 



alata, C. bispinosa, C. ciliata var. curta, C. 

 ciliata var. emaciata, tumida, Ulrich, 

 1890, Jour. Cin. Soc. Nat. I list., vol. 13, 

 pp. 108 to 111, Hud. Riy. Gr. ; and C. 

 antespinosa, ('. informis, C. minima, 

 C papillosa, pp. 186 to 188, Up. Held, 

 or Ham. Gr. ; and 0. punctata, p. 186, 

 from the Niagara Gr. 



ciliata, Emmons, 1855, (Beyrichia ciliata,) 

 Am. Geo., p. 219. Hud. Riv. Gr. 



duryi, S. A. Miller, 1874, (Beyrichia 

 durvi,) Cin. Quar. Jour. Sci., vol. 1, 

 p. 232, Hud. Riv. Gr. 

 Oyclus, DeKoninck, 1841, .Mem. Acad. Sci. 

 Bruxelles, vol. 14, p. 18. [Ety. kuklos, 

 circle.] Carapace longer than wide, 

 somewhat hemispherical, narrow, 

 smooth border, indented behind shield; 

 divided down its center by a dorsal 

 ridge, from which radiate ribs or trans- 

 verse wrinkles. Type O. radialis. 



americana, Packard, 1886, Mem. Nat. 

 Acad. Sci., vol. 3, p. 143, Coal. Meas. 

 Cypridina, Edwards-Milne, 1838, Lamarck's 

 Anim. Sans Vert., vol. 5, p. 178. 

 [Ety. from the genus Cypris.] They 

 have two eyes situated toward the 

 middle of their bivalve test, and a 

 caudal appendage at the posterior 

 border, armed with spines disposed as 

 the teeth of a comb. Edwards men- 

 tioned no type when founding the genus 

 upon the living Ostracoda, but it is 

 very evident the genus is not known in 

 Palaeozoic rocks. 



herzeri, Ulrich, 1890, Jour. Cin. Soc. Nat. 

 Hist., vol. 13, p. 209, Keokuk Gr. 



