8 North American Palaeozoic Crustacea. 



Belinurus, Koenig, 1820; Icones Fossilium Sectiles, pi. 18, fig. 230. 



Gen. Char. — Belhiurus (Koenig) Bailey. "General form suborbicular. 

 Head or cephalic shield semicircular, slightly arched ; the central 

 portion (glabella ?) prominent and declining towards the circnmfer- 

 ence surrounded with a flattened margin, and terminating at its poste- 

 rior angles in long spines. Body composed of 5 segments which 

 terminate in spines and diminish gradually towards the posterior 

 extremity. Tail or caudal portion small, with a few slightly radiating 

 divisions, to which is articulated an elongated spine (/e/sow)." Bailey, 

 Annals & Mag. Nat. Hist., 3d series, London, vol. 11, 1863. 



Dance, Meek & Worthen, 1865 ; Proc. Acad. Nat. Sci. Phila., vol. 17, 

 p. 43 ; see Pi-estwichia. 



Lacoei, Packard, 1885; Am. Naturalist, vol. 19, p. 292. Carboniferous. 



LacoM, Packard, 1886 ; Mem. Natl. Acad. Sci., vol. 3, p. 149, pi. 5, fig. 5. 

 Beyrichia, McCoy, 1846 ; Silurian Fossils Ireland, p. 58. Type Deyrichia 

 Klodeni, McCoy. 



Gen. Char. — Bivalve, " rotundate-quadrate or longitudinally oblong, ends 

 unequal ; anterior, posterior, and dorsal margins convex, and sur- 

 rounded by a sharply-defined, narrow, tumid border or rim ; ventral 

 margin simple, straight, or concave ; sides tumid, strongly divided 

 into lobes by very deep, nearly vertical furrows extending from the 

 ventral more or less towards the dorsal margin." McCoy, Brit. Palseo- 

 zoic Fossils, p. 135. 



fequilatera. Hall, 1860 ; Canadian Katuralist, vol. 5, p. 158, fig. 20. 



Silurian. 



aequilatera, Dawson, 1868 ; Acadian Geology, p. 609, fig. 217. 



Atlantica, Billings, 1865; Palaeozoic Fossils, vol. 1, p. 300. Quebec. 



bela, Walcott, 1883 ; Desc. new species Trenton group, p. 7, pi. 17, 

 figs. 11, 11a. Trenton. 



bela, Walcott, 1884 ; 35th Kept. New York State Mus. Nat. Hist., p. 213, 

 pi. 17, figs. 11, 11 a. 



Chanil)ersi, Miller, 1874 ; Cincinnati Quart. Jour. Sci., vol. 1, p. 234, 

 fig. 27. Hudson River. 



Chambersi, Hall & Whitfield, 1875; Pal. Ohio, vol. 2, p. 104, pi. 4, 

 figs. 11,12. 



ciliata, Emmons, 1855 ; American Geology, vol. I, pt. 2, p. 219, fig. 74c. 



Hudson River. 



ciliata. Miller, 1875 ; Cincinnati Quart. Jour. Sci., vol. 2, p. 351. 

 Compare B, tumifrons, Hall. 



Cincinnatiensis, Miller, 1875 ; Cincinnati Quart. Jour. Sci., vol. 2, p. 350, 

 fig. 25. Hudson River. 



Cincinnatiensis, Walcott, 1876 ; Trans. Albany Inst., vol. 10, p. 23. 



clatlirata, Jones, 1858; Annals and Mag. Nat. Hist., London, 3d series, 

 vol. 1, p. 242, pi. 9, fig. 1. Niagara. 



Dagon, Clarke, 1885; Bull. U. S. Geol. Survey, No. 16, p. 29, pi. 2, 

 figs. G, 7. Genesee Shales. 



