SYNOPSIS OF GENERA. xxiii 
transverse frontal suture. Hypostoma small, elongate-sub-quadrate; sides 
gently concave; posterior edge emarginate. 
Thorax composed of thirteen broad segments; axis tapering backward. 
Pygidium bearing six to eleven distinct annulations; axis regularly tapering 
from the thorax. 
Genus HOMALONOTUS. Kcenig. 1825. 
1822. Asaplius, Beongniart. Hist. Nat. Crust. Fossiles. 
1825. Homalonotus, Kcenig. leones foss. seetiles. 
1825. Asa^hus, Deslongchamps. Mem. Soc. Linn, ilu Calvados. 
1828. Asaphus, Dalmajt. Vet. Acad. ArsLeiatt. 
1832. Bipleura, Trimerus, Green. Monog. Ti-ilob. N. America. 
1835. Homalonotus, Bronn. Lethsea Geog-nostica. 
1837. Trimerus, Green. Amer. Jour. Science. 
1839. Homalonotus, Emmrich. Be Trilob. Disseid. 
1839. Homalonotus, Murchison. Silurian System. 
1840. Homalonotus, Milne-Edwards. Hist. Nat. Crustacds. 
1840. Homalonotus, Bronn. Leonhardt’s Jahrb. fiir Min. , 
1841. Homalonotus, Phillips. Palieoz. Foss. Cornwall, Devon and Somerset. 
1842. Bipleura, Conrad. Jour. Acad. Nat. Sci. 
1842. Homalonotus, D'Archiac and De Verneuil. Trans. Geol. Soc. 
1842. Bipleura, Vanuxem. Kept. Third Dist. N. Y. ' 
1843. Homalonotus, Bipleura, Hall. Kept. Fourth Dist. N. Y. 
1843. Bipleura, HomalonoUis, Goldfuss. Neues Jahrb. fur Min. 
1843. Homalonotus, Castelnau. Ess. sur le Syst. Sil. de I’Amer. Sept. 
1843. Homalonotus, Goldfuss. Neues Jahrb. fiir Min. 
1843. Homalonotus, F. A. Rcemer. Verstein. des Harzgeb. 
1844. Homalonotus, Sedgwick and Murchison. iElt. palseoz. Geb. im Norden von Deutschl. und Belgien. 
1844. Homalonotus, Eichwald. Sil. Syst. in Esthland. 
1846. Homalonotus, Burmbister. Organ, der Trilob. 
1845. Homalonotus, Emmrich. Neues Jahrbuch fiir Min. 
1847. Plossiacomia, Corda. Prodr. Monog. bohm. Trilob. 
1849. Homalonotus, Rouault. Bull, de la Soc. g^ol. de France. 
1849. Homalonotus, Salter. Ann. and Mag. Nat. Hist. 
1850. Homalonotus, the Brothers Sandberger. Verst. Rhein Sch. Syst. 
1850. Homalonotus, De Verneuil. Bull. Soc. g6ol. de France. 
1851. Homalonotus, McCoy and Sedgwick. Synopsis Brit. Pal. Foss. 
1852. Homalonotus, Hall. Pal. N. Y., vol. ii. 
1852. Homalonotus, Barrandb. Syst. Sil. Boh^me, vol. i. 
1852. Homalonotus, F. A. Rcemer. Beitr. ii, zur Harzgeb. 
1854. Homalonotus, Wirtgen and Zeiler. Verhandl. d. Naturhist. Vereins. 
1855. Homalonotus, F. A. Rcemer, Beitr. hi, zur Harzgeb. 
1855. Homalonotus, Angelin. Palieontologia Scandinavica. 
1858. Hmnahmotus, Hoffmann. Trilob. Russlands. 
1858. Homalonotus, Bigsby. Quart. Jour. Geol. Soc., vol. xiv. 
1859. Homalonotus, Hall. Pal. N. Y., vol.-hi. 
1860. Homalonotus, Eichwald. Lethsea Rossica. 
1860. Homalonotus, Hall. Canad. Nat. and Geol. 
1862. Homalonotus, Hall. Fifteenth Rept. N. Y. State Cab. Nat. Hist. 
