40 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 53 



curvature to the base of the eye lobes ; curving over and around the 

 eye lobes, they pass forward and a little outward to the front margin ; 

 the distance between the eye lobes and margin is about the length 

 of the eye lobe. 



Thorax with eight segments; axial lobe moderately convex, about 

 as wide as the pleural lobes in partially conipressed specimens ; on 

 the outer side of each segment a rounded, transverse node or ridge 

 is separated from the main body of the segment by a slightly oblique 

 furrow transverse to the segment ; the furrows are similar to those 

 crossing the occipital ring; pleural lobes slightly convex and with 

 the extremities of the pleurae bending slightly downward ; each 

 pleura has very narrow, raised margins next to the axial lobe that 

 gradually broaden and slope inward out to the slight geniculation, 

 v^rhere they form an elongated node with straight outer edge, which, 

 touching against the nodes upon the adjoining pleura, forms an 

 elongated, rounded node transversely divided by the line separating 

 the pleurae; an elongated, tapering, rounded node, with its base 

 at the dorsal furrow, occupies the inner half of the pleura ; a narrow 

 groove on each side of the node united to form a shallow pleural 

 furrow that terminates within the somewhat abruptly pointed outer 

 extremity of each pleura. 



Pygidium of medium size, about one-fourth the length of the 

 dorsal shield ; anterior margin nearly transverse, except where it 

 bends backw^ard near the outer ends ; posterior outline semicircular ; 

 axial lobe moderately convex and tapering gradually toward the 

 posterior section ; it is divided by four transverse furrows into four 

 rings and a terminal segment ; four anch3^1osed pleural segments are 

 outlined on the pleural lobes on each side of the axial lobe by fur- 

 rows that progressively curve backward from the first to the pos- 

 terior adjoining the terminal segment; the furrows all terminate 

 within the narrow, slightly flattened border. 



Surface finely granulose. 



Dimensions. — A dorsal shield 13.5 mm. in length has the follow- 

 ing dimensions : 



Cephalon : mm. 



Length 50 



Length of eye lobe 0.9 



Width at posterior margin 9.0 



Width of glabella at posterior margin 2.4 



Thorax : 



Length 5-5 



Width 8.5 



Width of axial lobe at first segment 2.3 



Width of axial lobe at eighth segment 1. 9 



