CYBELE BELLATULA. L25 



1881. Cybele bellatula, Schmidt, Kev. Ostbalt. Silur. Trilob., pt. i, p. 203, pi. xiii, figs. 9—13 ; pi. xv, 

 figs. 1-5. 



1882. Cybele bellatula, Brogger, Die Silur. fit. 2 und 3, p. 136, pi. vi, figs. 2, 2 a, 2 b. 

 1888. Cybele bellatula, Wigand, Zeitsc-hr. deutsch. geol. Gesell., vol. xl, p. 88, pi. x, fig. 15. 



1901. Cybele bellatula, Lindstrom, K. Svensk. Vet. Akad. Handl., vol. xxxiv, No. 8, p. 52, pi. iv, fig. 2. 



Remarks. — Certain head-shields from Dow Hill bear a close resemblance to 

 C. bellatula (Dalman), and are undoubtedly distinct from other British species. The 

 glabella in these Girvan specimens is oval, broadest across the middle, with three 

 pairs of lateral lobes marked off by deep furrows, of which the two posterior 

 furrows are straight, almost horizontal, reach more than one third across the 

 glabella and deepen at their inner ends. The anterior furrows are oblique and cut 

 into the anterior end of the glabella, defining between them a triangular frontal 

 lobe. The axial furrows are deep. The occipital ring is prominent, rounded, and 

 widest in the middle. The fixed cheeks are nearly twice as wide as the glabella, have 

 a convex surface, and towards the genal angle are bent downwards and backwards. 

 The eye-stalks are at the level of the anterior lateral lobes of the glabella, and are 

 stout and prominent, rising up almost vertically from the cheek. They are distant 

 from the glabella about half its width, and are connected with it by a faint ridge. 

 The cheeks are finely pitted, but the glabella seems to be feebly granulated. The 

 neck-segment is narrow and smooth, but widens towards the genal angles. A 

 strong neck-furrow separates it from the cheek. 



There does not appear to be any marked point of difference between these 

 head-shields and those of G. bellatula, except that the eye is not placed quite so far 

 forward and is directed rather laterally instead of anteriorly. Free cheeks probably 

 belonging to this same form are found at Dow Hill and Balclatchie ; they are of 

 triangular shape with an elevated pitted surface bearing a tall stalked eye, and the 

 rounded border is produced anteriorly into the characteristic pointed process. In 

 one specimen belonging to the same species we find the head-shield attached to 

 eight thoracic segments. The free ends and extra-fulcral portions of the pleura? 

 are broken off, but each pleura is seen to be slightly contracted at its base on the 

 axial furrow ; the pleural furrow is narrow and does not arise quite at its base but 

 runs out to the fulcrum nearly parallel with the anterior edge of the pleura; the 

 portion of the pleura behind the pleural furrow is nearly twice as wide as the part 

 in front, and is more strongly raised and prominent, bearing traces of one or two 

 tubercles in addition to the general granulation which covers the whole surface of 

 the pleura. The axial rings are furnished with low rounded lateral nodes on the 

 axial furrows. 



There are certain pygidia from Dow Hill and Balclatchie which are probably 

 referable to this species. In one specimen from Dow Hill there are three thoracic 

 segments attached; the pleura? are strongly curved backward, and produced into 

 long free rounded spines; the rounded surface of the pleura is divided as far out as 



