7 1 PALEONTOLOGY OF NEW YORK. 



tubercles. Then' appears to have been also a strong spine near the ocular 

 node jusl outside the lateral lobes. The occipital furrow is broad and 

 -hallow over the axis, deeper along the abruptly sloping sides of the cheeks; 

 the occipital ring is ver\ broad, depressed-convex, with a gentle anterior and 

 an abrupt posterior slope, and narrows rapidly towards the axial furrows; 

 on its posterior edge it bears a row of from six to eight strong clavate 

 tubercles. 



Cheeks separated from the lateral lobes by a faint furrow, which leaves the 

 position of the eyes elevated, and gives to the lixed portions of the cheeks 

 an abrupt anterior and posterior slope. The free portion, as far as can be 

 judged from two fragments, was somewhat constricted or narrowed beyond 

 the terminations of the facial sutures, and its posterior margin carried a 

 series of more or less irregular, tubercled spines. The genal extremities 

 were acute and attenuate, and the anterior margin regular. 



The surface of the cephalon is covered with coorse tubercles which are 

 largest on the posterior extremity of the anterior lobe, but are almost all 

 absent on the median depression behind this lobe, and are obsolete on the 

 constricting furrow about its base. 



Thorax. The character of this part of the animal is known only from two 

 impressions, one of a segment of a small individual, the other the axial arch 

 of the segment of a large example. The segment shows a relatively wide 

 and strongly arched axis and narrow pleurae deflected at about the middle of 

 their length. The axial arch bears two strong, straight, divergent spines, 

 reaching a height equal to the width of the axis, and apparently directed 

 posteriorly. 



Pvgididm semi-circular in general outline, wider than long; strongly spinose on 

 the lateral and posterior margins; anterior margin nearly transverse. 



Axis relatively wide, being about one-third as wide as the shield on 

 the anterior margin, and tapering rapidly to an elevated termination at a 

 point about hall' way across the pygidium. It bears two annulations, behind 

 which are situated a pair of conspicuous tubercles, and between this point 



