718 



ARTHROPODA 



PHYLUM VII 



Bathyurus Billings (Fig. 1381). 



Glabellar furrows faint or absent. Pygidiuui 

 with four pairs of smooth ribs, and a long, pro- 

 minent axial lobe. Ordovician ; North America, 

 including Beekmantown beds of Newfoundland. 



Petigurus Raymond. Cephalon like Bath- 

 yurus. Pygidium with nodose ribs and strongly 

 annulated axial lobe. Ordovician ; Canada and 

 Ireland. 



Bathyuriscus Meek. Glabellar furrows 

 deeper, eyes further forward, and pygidium 

 larger than in Bathyurus. Middle Cambrian ; 

 North America and Asia. 



Bathyurellus Billings. Glabella low, smooth, 

 pointed in front. Cephalon and pygidium 

 with broad concave borders. Ordovician ; North 

 America. 



Asaphidae Burmeister. 



Family 11. 



Ofisthoparia with large., sub -equal haul and 



Fig. 13S1. abdomen shields, inominent eyes, eight segments in 



Bnthyurnsiunfiispinus Waicoti. Black River the thorax, and toith a median vertical suture in 



KoS"^ ' ^'''^'°'^' ^•^'- "" ''' ^*^"" the doublure of the cephalon. Middle Cambrian 



to Ordovician. 



Facial suture 





Subfamily A. Ogygiocarinae Raymond. 



Asaphidae with hijpostoma rounded or pointed behind. 



Ogygiocaris Angelin {Ogygia auct. non Brong.) (Fig. 1339). Pygidium with flat, 

 furrowed ribs. Axial lobe very narrow, 

 marginal in front of 

 glabella. Ordovician ; 

 Eiu'ope. 



Ogygopsis Wal- 

 cott (Fig. 1382). 

 Similar to Ogygio- 

 caris, but with eye- 

 lines, and eyes small 

 and far apart. Middle 

 Camljrian ; British 

 Columbia. 



Mega laspis Ange- 

 lin (Fig. 13 83). 

 Glabella short, 

 cephalon and pygi- 

 dium nearly smooth 

 and sometimes 

 pointed. The facial 

 sutures meet in a 

 point far forwaid of 

 the glabella. Ordovi- 

 cian ; Europe, Asia, 

 and rarely North 

 America. 



■^ 



S^' 



Fig. 1382. i 



OgygupsiSjldotzi (Rotiiiiigcr). Miilille Cam- 

 brian ; Mount Stepliuu, British Cohinibia. 

 i/i (after Walcott). 



Megalaspis extenuata Aug. Ordo- 

 viciau ; ijast Gotlaiidj Sweden, 

 i/i (after Angelin). 



