268 WANNER 



and forward thrust of the large frontal segment of the glabella. A low 

 narrow ridge extends along the posterior margin of the cephalic shield. 



The anterior marginal fold is striated by closely placed parallel 

 lines, conforming to the curvature of the perimeter and occasionally 

 inoscvilating. 



There are prominent and moderately long genal spines and the base 

 of a meso-occipital spine. 



The anterior part of the glabella, evidentlv originally hemispherical 

 and very prominent, is flattened and pushed forward in all the speci- 

 mens found. The glabella is widest across the middle of the promi- 

 nent frontal lobe, uniformly narrowing to the posterior lobe. The 

 posterior part is divided into four transverse ridges by the occipital 

 furrows and three additional pairs extending nearly to the top. 



Eyelobes crescentiform and prominent, with a raised rim around 

 the outer margin, cin-ving outward from the posterior part of the frontal 

 lobe of the glabella and terminating in front of the occipital furrows. 



Thoracic segments seventeen ; niedian lobe strongly convex, the 

 base of a spine extending across the middle of each segment. 



Pleura slightly curving part way and then strongly falcate ; chan- 

 nelled with a broad groove, extending to half the length of the pleura 

 and where the grooves terminate, presenting a prominent line of de- 

 marcation, beyond which the flattened and broad extremities curve 

 more sharply downwards. Posterior pairs of pleura strongly incurv- 

 ing and inclosing the pvgidium. 



Beyond the termination of the pleural groove, closely placed trans- 

 verse folds, overlapping each other at short intervals, finely fret the 

 surface with short, curved, inosculating lines. 



The strongly falcate ends of the pleura increase in relative length 

 towards the pygidium, attaining their greatest extension shortly ante- 

 rior to the ultimate pair of pleura. 



With the exception of the falcate ends of the pleura and part of the 

 pygidium a network of incised lines (PI. xxxi, fig. 2) ornaments the 

 surface dividing it into minute hexagonal, or pentagonal, plates. In 

 all casts of the surface the inosculating lines are raised above the en- 

 closed spaces. 



Pygidium small, circular ; extending but slightly further longitudi- 

 nally than its transverse width along the line of attachment. The 

 posterior margin (PI. xxxii, fig. 4) parted in the middle by a trian- 

 gular incision penetrating about one third of the distance across. In 

 this specimen, the triangular incision is open and the pygidium, to- 

 gether with the thoracic segments, somewhat fore-shortened ; in PI. 



