XXXIV 



SYNOPSIS OF GENERA. 



Sub-gencS CORYCEPHALUS, n. sub-gen 

 Diagnosis. The entire frontal and lateral 

 margins of the cephalon bear a single row of 

 widely separated denticulations, which may 

 be acute and triangular or broad and sub- 

 quadrate. 



Sub-genus CHASM OPS, McCoy. 1850. 



1837. Asaphus (partim), Murchisoh. Silurian System. 



I83S. Trilobites (partim), Sars and Bokck. Gaea Norvegica. 



1843. Phacops (partim), Portlock. Geolog. Rept. Tyrone. 



1845. PJiacops [partim), Emmrh h Neues Jahrb. fur Min. 



1846. Phacops (partim), Bdrmeister. Organiz. Trilobites. 



1848. Dalmania, Sai ikii. Mem. Geol. Suit, United Kingdom. 



1849. Phacops partim), Salter. Mem. Geol. Surv. United Kingdom. 



1850. Chasmops, McCoy, bin. and Mag. Nat. Hist. 



[851. Chasmops, Odontochile, McCoy. Synops. Pal. Poss. Woodwardian Mus. 



1852. Chasmops, Angelin. Palseontologica Suecica. 



1853. Phacops (Dalmania), Salter. Geol. Surv. Decade vii. 

 1864. Chasmops, Salter. Monogr. Brit. Trilobites. 



181 I. Phacops (partim), Linkarshok. Verstergotl. camb. oeh. siltir. Aflag. 



1^71. Phacops [partim), Steinhardt. In preuss. Geschieb. get'. Trilobit. 



1876 Dalmanites (partim), Hall. Illustrations of Devonian Fossils. 



|s7i;. Chasmops, C. F. Rcemkr. Lethaea palseozoica. 



]s7s Phacops (partim), Angelw. Paljeontologia Scandinavica. 



1885. Chasmops, Zittel. Handb der Pala tologie. 



Diagnosis. Genal angles usually produced into 

 spines. Frontal lobe of the glabella large, trans- 

 verse and not intersected by the facial sutures. 

 Lateral lobes unequal, the first and second pairs 

 being coalesced and the third pair nearly obso- 

 lete. Pygidium large, sometimes with a terminal 

 -pine. 



