194 F. R, Cowper Reed — On Brachymetopus. 



This description may be amplified as follows (using only the type- 

 specimens) : — Head-shield semicircular, moderately convex, with 

 strong raised rounded border increasing slightly in width towards 

 the front, and separated off by a deep furrow. Genal angles furnished 

 with slender divergent smooth spines, less than half the length of the 

 head-shield. Neck-segment strong, marked off by deep furrow. 

 Glabella convex, subcylindrical, about twice as long as wide, and 

 measuring about one-fourth the width and two-thirds the length of 

 the head-shield. At its base is a pair of small nodular basal lobes, 

 in most specimens quite inconspicuous. Two large tubercles are 

 situated in a line down the middle of the glabella, followed by 

 a similar median one on the occipital segment. Occipital segment 

 strong, rounded, separated off by deep furrow. On cheeks at 

 anterior end of glabella is a pair of large tubercles, one on each side. 



1 1 



Brachymetopus StrzelecTcii, McCoy. 



Fig. 1, the head-shield, and Fig. 2, the pygidium (restored). Restorations founded 

 on the type -specimens. Enlarged about 8 times natural size. Carboniferous 

 Limestone : New South Wales. 



No facial sutures visible. Eyes prominent, reniform, less than half 

 the length of the glabella, distant from axial furrows about one-third 

 the width of the cheeks, and about their own length from posterior 

 margin. Surface of head-shield, including glabella, border, and 

 neck-segment, rather coarsely tuberculated. An indistinct ring of 

 larger tubercles surrounds eyes, and a large tubercle is situated 

 at each end of eyes on inner side. Thorax unknown. Pygidium 

 semicircular, slightly convex, with spinose margin. Axis broad, 

 conical, about one-third the width of pygidium at front end ; tapers 

 rather rapidly to obtuse point, nearly touching border ; consists of 

 9-10 segments, of which eight rings are distinct and completely 

 tuberculated across; the 1st, 3rd, 5th, and 7th rings have in addition 

 a large median tubercle. Lateral lobes composed of six (? seven in 

 some) pairs of pleurae, of which the last pair is very small ; each 

 pleura is gently curved, and is divided unequally by a strong 

 longitudinal furrow into a broader, raised, rounded, posterior ridge 

 and a narrower, anterior ridge. The posterior ridge of each 

 pleura crosses a distinct raised, rounded border which surrounds the 

 pygidium and bears a large tubercle at the spot where it crosses 

 and a single median one behind the axis. The posterior pleural 

 ridges are prolonged into short, recurved, equidistant, and subequal 

 spines, projecting freely beyond the margin. (In one specimen there 



