24 S.MITHSOXIAX MISCELLAXHOUS COLLECTIONS VOL. 53 



in outline exclusive of the postero-lateral limbs ; the latter are 

 elong'ate, subtriangular in outline, and with a narrow, transverse 

 furrow \vithin a rounded rim of medium width. Fixed cheek about 

 two-thirds the w^dth of the glabella and merging posteriorly into the 

 postero-lateral limb and anteriorly extending to the frontal rim ; 

 there is no defined frontal limb, owing to the glabella extending to 

 the furrow within the frontal rim ; palpebral lobe narrow, rounded, 

 about one-half the length of the cranidium, and with its outer rim 

 extending across the fixed cheek as a narrow ocular ridge nearly 

 parallel to the frontal rim of the cranidium ; the palpebral lobe 

 terminates a short distance back of the frontal margin of the gla- 

 bella. Glabella subquadrangular ; slightly narrower at the broadly 

 rounded front than at the occipital ring, moderately convex ; divided 

 b}- four faint, transverse furrows into three transverse lobes, an 

 anterior, terminal lobe and an occipital ring ; the faint, transverse 

 furrows terminate on each side in round pits a short distance from 

 and within the margin ; occipital ring narrow and rounded. Free 

 cheeks unknown. The facial sutures cut the posterior margin on 

 each side a short distance from the genal angle and extend inward 

 and slightly forward to the base of the eyes ; curving over the eyes 

 they extend forward with a slight outward direction, so as to cut 

 the front margin on a line with the outer edge of the palpebral 

 lobe. 



Thorax with eleven nearly transverse segments ; the axial lobe 

 is convex and one-half the width of the pleural lobes ; the segments 

 of the axial lobe have a deep transverse furrow with the margins 

 elevated ; the doublure on the front margin of each segment curves 

 downward, so as to pass beneath the downward slope of the pos- 

 terior half of the next segment in advance of it ; the extremity of 

 each segment curves slightly forw-ard. so that the furrow passes 

 (Xit upon the pleura a little in advance of its position at the center 

 of the axial lobe and in front of the pleural furrow ; the pleura is 

 straight, nearly flat, and terminating in a blunt, straight margin 

 without spine or backward curvature ; the most careful examination 

 fails to reveal spine or falcate extremity ; the entire side of the 

 thorax appears as though a sharp knife had cut ofif the ends of all 

 the pleura from the cephalon to the pygidium : the pleural furrows 

 of each segment originate on a low swelling between the axial and 

 pleural lobes of each segment and extend directly outward to nearly 

 the end of the segment, where they fade away, so as to leave the 

 end of the segment flat ; the ]ileural furrows are about one-third of 

 the width of the segment and arch forward a very little between 

 its two extremities. 



