398 ON A NEW TRILOBITE FROM BOWNING, 



Thorax with the axis promiaeDt and about as wide as 

 the side-lobes, nearly as wide as long, and as far as can 

 be seen from the specimens yet obtained consisting of nine 

 segments, no granulation noticeable probably from imperfect pre- 

 servation, axial groove not defined, or may be said to be absent. 

 At its extremity each pleura carries an abnormally large spine 

 exceeding four times its own length ; the anterior edge of each 

 pleura is continued into a somewhat paddle-shaped appendage 

 which bears the appearance of having been articulated near the 

 middle. The spines are directed backwards increasingly from the 

 first to the last, so that those from the 7th, 8th, and 9th pleurae on 

 each side are parallel with the axis. At its articulation with the 

 cephalic-shield the thorax is less wide than the shield ; hut at the 

 third segment their transverse measurements are equal. The 

 pleurae prominently ridged ; at their junction with the axis curved 

 forward, compressed laterally, swollen and have between each a 

 rather deep depression forming an interrupted axial groove. 



Pygidium triangular, two and a-half times as wide as long, side 

 lobes equal in length, granulation distinct; axis prominent, two- 

 thirds the length of pygidium, no true segmentation but crossed 

 by one raised arch ; side-lobes undivided, traversed by two pairs of 

 lateral elevations or pads, one along the front edge, the other pair 

 from the ring of the axis, one irom each side, which curve back- 

 wards and cut the margin of each side-lobe appi'oximately at one- 

 third of the lobe's marginal measurement, i.e., they divide each 

 lobe into two portions, so that at the edge the anterior portion is 

 one-thii'd of the other. From these two elevations project two 

 spines, inclining towards each other, and not so proportiouately 

 large as those of the pleurixj, or genal angles. These are the only 

 spines on the pygidium. The lobes are flat, but for the elevations 

 just referred to, except along the edges which are slightly curved 

 downwards. The larger granulations appear to be in rows. 



The prominent features of this species are its very large spines, 

 facetted eyes, and the paddle-shaped attachments to the pleurae, 

 which distinguish it from all the species of Acidaspis that I am 



