ARTHROPODA 



PHYLUM VII 



fl K' I 1-1 ri.i ; r \ / i^xi. 



724 



, 1 . . cn.n elevated on conical promineiices ; tlioracic segmentB 



epistomal plate ; eyes small, «levatedj^^^ _ ^^^.^.F^^^ ^^^^^^^^^^ triangulär. Ordo- 



viciaii and Silurian ; Europe, Asia, and America. 



Gyhele Loven. Similar to Encnnurus, but 



with the ribs of the pygidium turning back 



sliarply, parallel to the axis. Ordovician and 



,, ,,,, Silurian ; Europe and America. J 



Fi(i. 1400. "M 



Fio. 13l»li. Encrinurns hohemicus ^ 



Encrinurus punc (liarrande). Silurian p ii„ £. Calymenidae Miliie Edwards, 



taiTEmmrich.'^Sil- (Etege E) ; Lochkow. i^amiiy ^. y , ,, , 



urian ; Qotiand. Bohemia. Proparia wüh tUrteen Segments, the hypo- 



aoma notched bekind, and attached to an ^AümM plate. Free cheeks narro^, the 

 facial sutures cutting the 

 margin almost exactly-\in 

 the genal angles. Oi^dovician 

 to Devonian. 



Galymene Brongniart 

 (Figs. 1398, 0; 1401). 

 Glabella prominent, strongly 

 lobed, with two or three 

 pairs of lateral furrows. 

 Ordovician to Devonian ; 

 Europe, Asia and America. 



Pharostoma Corda. 

 Glabella prominent, very narrow at the front, with 



two pairs of glabellar furrows. Long genal spines 



present. Ordovician; Europe. 



Homalonotus Koenig. Axial lobe wide, cephalon 



Short and trilobate in front, cheeks forming high 



mounds crowned by the eyes. Silurian; Europe 



and Nova Scotia. 



Trimerus Green (Fig. 1402). Cephalon longer 



than in the preceding, not trilobate in front, free 



cheeks narrow. Silurian and Devonian ; world-wide 



distribution. 



Dipleura Green (Fig. 1 3 9 8, D). Axial lobe wide. 



Pygidium smooth. Devonian ; Europe and America. 



Family 3. Cheiruridae Salter. Fig. 1402. 



Trimerus delphinocephalus Green. 

 Propana with small free cheeks, whose anterior ends ■ Silurian ; Lockport, New York. 



are separated hy the glabella. Pygidium small with 



pleura ending in spines. Thorax with nine to eighteen Segments. Ordovician to Devonian. 



Fig. 1401. 



Galymene meeU Foerste. 

 Ordovician ; Cincinnati, Ohio. 



X Vi- 



Subfamily A. Cheirurinae Raymond. 



Cheiruridae with eleven segments in the thorax {rarely nine to thirteen), and four 

 Segments in the pygidium. 



Gheirurus Beyrich (Figs. 1398, E ; 1403). Glabella smooth, more than one-third 

 the total width of the cephalon ; pygidium with six or seven sub-equal spines. 

 Ordovician and Silurian ; Europe, Australia and America. 



Geraurus Green (Fig. 1341). Glabella pustulose, one-third or less the total width 

 of the cephalon ; pygidium very small, with the first pair of spines very long, the 

 others short or absent. Ordovician ; Europe, Asia, and America. 



