502 SILURIAN TRILOBITES OF XEW SOUTH WALES, vi., 



rower than the raised medial parts; both ridges and furrows dis- 

 appear just before reaching the margin; the tirst lobe of each 

 pleura is distinctly falcate and wider than the others, the second 

 is slightly falcate, the others are straight. 



06s.— This is the first Bronteus with a bifurcate central pygidial 

 rib to be described from New South Wales. It resembles, in 

 some features, B. palifer Barr., B. anyusticeps Barr., and B. 

 trmisvey^sus Barr. With the first of these, it agrees in the char- 

 acter of the pleural ribs, in having the axis wider than the 

 pleurie, wide valleys between the ribs, and in the trilobation of 

 the rudimentary axis; but differs from it in having the bifurcate 

 portion relatively much shorter, the lower portion concave, and 

 in contour, itc. With B angusticeps, it agrees in the character of 

 the articulating border, and the pleural segments, but differs in 

 having a much longer bifurcation of the central ridge or rib, 

 stronger pleurae, and the axis wider than the pleurse. B. trans- 

 versus Barr., agrees with our species in contour, trilobation of 

 the axis, and in the relative length of the bifurcation of the 

 central rib, though this does not appear to be as long as it is in 

 ours. The axis in B. transversus is narrower than the pleurae, 

 and the whole tail is flat, instead of being inflated in the anterior 

 half and concave in the posterior portion, as is the case with 

 ours; but, between that and the present fossil, there is little 

 other relationship. 



Loc. and Uor. — Molong, Parish Bell, County Ashburnham: 

 Molong Limestone. (?)Upper Silurian. 



Bronteus angusticaudatus, sp.nov. 

 (Plate XX vi., tigs.9, 10.) 

 Sp. Chay^s. — Pygldiutn': length and width practically equal, 

 upper surface smooth, undersurface distinctly covered with con- 

 centric striae, gently convex medially and subconcave towards the 

 margin: axis ill-defined, gently tumid; axial grooves very faint; arti- 

 cular border straight, reaching nearly to the lateral angles, which 

 are slightly rounded; pleurae consist of six ribs on each side of the 

 central one, separated by distinct sulci, less than half the width 

 of the ribs, and becoming effaced just before reaching the margin; 



