36 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 55. 



NEOLENUS SUPERBUS, new species 



Plate 4, Figures 1-5 



Dorsal shield large, longitudinally elliptical in outline, moderately 

 convex. Cephalon subsemicircular in outline, one-third of the 

 length of the dorsal shield ; bordered by a strong, slightly convex 

 outer margin that is continued at the genal angles into strong, sharp 

 spines that extend backward and slightly outward to about opposite 

 the fourth thoracic segment ; the posterior marginal border is 

 narrow next to the glabella, from where it gradually broadens to 

 the base of the genal spine ; between the facial suture and the 

 genal spine the margin arches abruptly forward, so as to throw the 

 base of the genal spine in front of the line of the posterior margin ; 

 a well defined but narrow furrow separates it from the fixed cheek. 

 Cranidium with a large glabella, narrow antero-lateral limbs, and 

 large postero-lateral limbs ; fixed cheeks narrow opposite the palpe- 

 bral lobes ; anteriorly they extend as a narrow, short section to the 

 front border, and posteriorly merge into the postero-lateral limb, 

 which is nearly as deep from the eye lobe to the posterior margin 

 as from the glabella to its postero-lateral angle ; palpebral lobe 

 narrow, short, and with its outer rim extended diagonally from and 

 across the fixed cheek to the dorsal furrow, next to the glabella. 



Glabella elongate, moderately convex; sides nearly straight, and 

 separated from the fixed cheeks by a narrow, strong furrow, slightly 

 wider where the sides touch the frontal border than at the occipital 

 furrow; front broadly rounded and subparallel to the anterior 

 margin of the cranidium ; surface marked by three pairs of short, 

 oblique furrows that extend inward and slightly backward about 

 one-third the distance across the glabella ; a small pit occurs in the 

 dorsal furrow at the antero-lateral angles, and from it a short, 

 obscure furrow extends directly inward for a short distance ; the 

 glabellar furrows are not at all prominent. Occipital ring narrow^ at 

 the ends, gradually becoming stronger and more convex toward the 

 center, where a strong, backward arching spine has its base ; occipital 

 furrow nearly transverse, shallow, and terminating in advance of the 

 furrows of the fixed cheeks. Free cheeks relatively small ; the body 

 rises with very little convexity from within the strong outer border 

 to the base of the short, low eye lobe. The facial sutures cut the 

 posterior margin a short distance wdthin the genal spine, curve 

 slightly outward across the border, and then inward with a gentle 

 sigmoid curve to the base of the eye lobe ; arching over the latter, 

 they extend forward with a slight outward arching across the 

 border, so as to cut the front margin on a line with the center of the 

 eve lobe. 



