146 MK. P. K. COWrEK REED ON THE FAUXA OF THE [May I909, 



to make out. The axis has the same shape, five or six rings, and 

 triangular terminal segment, as Billings figures and describes, and 

 the five rounded pleura? with free pointed recurved ends appear to 

 be closely similar. The length of our specimen with the spines 

 is about 12 millimetres, and its width about 20 to 24 mm. 



CXBELE CONNE3IARICA, Sp. 110V. (PI. VI, figS. 6 & 7.) 



Description : — Py gidium subpentagonal, as wide as long, greatest 

 width at the level of the posterior end of the axis, gently convex ; 

 lateral lobes bent down slightly in front but steeply behind. Axis 

 conical, tapering rather rapidly at about 30°, obtusely pointed, 

 annulated tor its whole length, more than a third of the width of the 

 pygidium at the anterior end and extending fully three-fourths of its 

 length'; composed of twelve or thirteen complete rings, separated 

 by strong equal furrows, deepest at the sides ; traces of lateral 

 nodules to rings. Axial furrows well marked. Harrow, elongated, 

 ridged postaxial piece extending from the tip of the axis to the 

 posterior margin of the pygidium, not sharply defined from the 

 lateral lobes. Lateral lobes composed of nine or ten pairs of 

 pleurse, of which the first three are subequal in size and the 

 remainder successively decrease in size and strength, the ninth being 

 very slender and short and lying close up against the last three 

 or four rings of the axis and not extending behind its tip ; faint 

 traces of a still smaller linear tenth rib are occasionally visible. The 

 first pleurse bend back strongly at about a third of their length, and 

 arch backwards almost parallel to the axis, reaching back as far as 

 its tip ; the following pleura? are less strongly curved, and become 

 successively straighter and subparallel to the axis, curving inwards 

 somewhat posteriorly. The first five pairs of pleurse end in free 

 obtuse short points on the margin, and are separated by strong 

 interpleural furrows ; the fifth pleura? curve inwards to meet in the 

 middle line behind the post-axial piece ; the other four or five pleurae 

 are enclosed, do not reach the margin, and end weakly against the 

 sides of the post-axial piece. A narrow anterior band is occasionally 

 visible on the anterior edge of the first three pleura?, but usually 

 they appear to be simple and unfurrowed. Surface of pygidium 

 granulated, with a few irregularly disposed tubercles on the pleura?. 

 Dimensions (average) : — 



Length of pygidium S millimetres. 



Width of pygidium 8 „ 



Length of axis 6'5 „ 



Width of axis at anterior end .. . 2"5 „ 



Remarks. — This species, of which only the pygidium is known, 

 appears to be allied to Gybele bellatula (Dalm.), 1 but the complete 

 condition of the axial rings and their much smaller number, as well 

 as the different characters of the pleura? of the lateral lobes, mark 



1 For references, see F. E. C. Reed, ' Lower Palaeozoic Trilobites of Girvan ' 

 pt. iii, Monogr. Palieont. Soc. vol. lx (1906) p. 124. 



