726 



ARTHROPODA 



PHYLUM VII 



Subfamily A. Dalmanitinae Reed. 



Phacopidae with more or less modified pentamerous segmentation of the glahella, and 



usually lüith large cranidia and pygidia. 



Dalmanitina Reed (Figs. 1353; 1356; 

 1398, i'^; 1407). Pentamerism of head well 

 marked, lobes of glabella distinct ; genal angles 

 rounded or with short spines. Pygidiiim 

 with few Segments, rarely more thaii ten. 

 Ordovician and 

 Silurian ; Europe. 



Dalmanües Bar- 

 raude (Figs. 1337 ; 

 1398, G-, 1408). 

 Frontal lobe of gla- 

 bella detached. Pygi- 

 dium strongly mucro- 

 nate, with twelve to 

 Devonian ; Europe and 



Dalmanitina socialis (Barr.). Ordovici? 

 D); Wesela, near Prague, Bohemia. Cephalon, 



Silurian and 



sixteen segments. 

 America. 



Asteropyge Corda {Cryphaeus Green). Pygidium with five 

 pairs of marginal spines, and sometimes a terminal spine. 

 Devonian ; Europe and America. 



Proholium (Ehlert. Cephalon with a snout-like anterior 

 Prolongation. Devonian ; Europe and America. 



Subfamily B. Phacopinae Reed. 



Phacopidae with glahellar furrows nearly or quite o 

 and pygidium small and rounded. 



Fig. 1408. 



Dalmanües limulurus 

 (Green). Silurian ; Lockport, 

 New York (after Hall). 



Phacopidella Reed (Acaste Goldfuss) (Figs. 1398, 1; 1409). 

 Glabella with three pairs of ^.^^^^^^ faintly defined lateral furrows. 



Ordovician and Silurian ; J^W^^^ Europe. 



Phacops Emmrich (Figs. ijjflfg^^ 

 furrows, except occasionally P J^j^^gpl the last pair, obsolete. Silurian 

 and Devonian ; world - wide fe'^ wkgmM^M distribution. 



Fio. 1409, 



Phacopidella dovmingiae 

 (Murch.). Silurian ; Lud- 

 low, England (after Salter). 



Fig. 1410., 



Phacops latifrons 

 Bronn. Devonian ; 



Gerolstein, Eifel 

 üistrict, Germany, 



Fig. 1411. 



Phacops sternbergi Barr. 

 Devonian (Etage G) ; Hostin. 

 Bohemia (after Barrande). 



Trimerocephalus M'Coy. Eyes small and far forward. Devonian ; Europe. 



