SYNOPSIS OF GENERA. 
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Sub-genus DICRANOGMUS, Corda. 1847. 
1846. Lidias (partim), Barrande. Notice piAlim. sur le Syst. sil. Bohfime. 
1847. Dicranogmus, Corda. Prodrom Moiiog. bohm. Trilob. 
1852. Lidias (partini), Barrande. Syst; Sil. BohSme, vol. i. 
1878. Lidias {partini), Angelin. Palaeontologia Scandinavica. 
Diagnosis. Dorsal furrows of the glabella 
parallel, becoming obsolete toward the anterior 
margin. Second lateral furrows transverse; 
second lateral lobes smaller than the first; 
third lateral lobes inconspicuous or obsolete. 
Palpebral furrows not conspicuous. 
Family, Probtid^. 
Genus PR GET US, Steininger. 1831. 
1826. Calymene, Dalman. Ueber Palseaden. 
1829. Calymene, Holl. Handb. der Petrefakten. 
1831. Proetus, Steininger. Mem. Soc. g6ol. de France. 
1832. Calymene, Goldfuss. Dechen’s Handb. d. Geognosie. 
1832. Calymene, Green. Mon. Trilob. North America. 
1837. Calymene, Hisinger. Lethsea Suecica. 
1837. Calyinsne, Quenstedt. Wiegmann Archiv. 
1838. Calymene, Green. Amer. Jour. Science. 
1839. Calymene, Conrad. Second Ann. Kept. Pal. N. Y. 
1839. Asaphus, Murchison, Silurian System. 
1839. Asaphus, Emmrich. De Trilob. Dissert. 
1840. Calymene, Milne-Edwards. Hist. Nat. Crust, fossiles. 
1842. Calymeiie, D’Archiac and De Vbrneuil. Trans. Geol. Soc. London. 
1842. Asaphus, Conrad. Jour. Acad. Nat. Sci. 
1843. Gerastos, Goldfuss. Leonhardt und Bronn’s Neues Jahrb. fiir Min, 
1843. Proetus, ,^onia, Burmeistbr. Organiz. d. Trilob. 
1843. Calymene, Hall. Kept. Fourth Dist. N. Y. 
1844. Gerastos, C. F. Rcbmbr. Rhein. Uebergangsgeb. 
1845. Gerastos, Emmrich. Neues Jahrb, fiir Min. 
1845. Proetus, Loven. Ofversigt. af. Kongl. Vetensk Akad. Forhandl. 
1846. Proetus, Barrande. Notice prdlim. sur Syst. Sil. Boh6me. 
1846. Proetus, Beyrich. Untersuchungen iib. Trilob. 
1846. Forhesia, McCoy. Synopsis Sil. Foss. Ireland. 
1846. Proetus, Rouault. Bull. Soc. gdol. de France. 
1847. Proetus, Xiphogonium, Corda. Prodrom Mon. bohm. Tidlob. 
1848. Proetus, Phillips and Salter. Mem. Geol. Surv. United Kingdom. 
1850. Trigonaspis, Cylindraspis, the Brothers Sandberger. Verst, d. Rhein. Scht. Syst. 
1850. Proetus, F. A. Rcemer. Beitr. i zur Harzgeb. 
1852. Proetus, Barrande. Syst. Silar. bohm., vol. i. 
1852. Proetus, Hall. Pal. N. Y., vol. ii. 
