124 TRILOBITES OF GIRVAN. 



strongly towards the extremity, and consist of ten or eleven simple pleural ridges, 

 separated by strong simple furrows. The pleural ridges terminate on the margin 

 in free, short, obtuse points. The axis is long, narrow, and slowly tapering, but 

 does not quite reach the posterior end of the pygidium. It is completely ringed, 

 but only the first 12 — 15 rings (in casts), or even fewer, are complete, the posterior 

 10 or more being incomplete in the middle. In some specimens only the first 8 — 

 12 aie complete. A similar variation is noticed by Schmidt in E. seebachi, Schmidt 

 (op. cit., p. 231) ; but in Portlock's type of E. multisegmentatus, and in the Haver- 

 fordwest specimens the rings are continuous as in the Girvan specimen. The 

 median space down the axis is smooth and bears no tubercles, but there are 1 — 3 

 tubercles frequently visible along the centre of the pleurae. 



Two pygidia from Shalloch Mill which should probably be ascribed to this 

 species have more the shape of E. seebachi as figured by Schmidt (op. cit., pi. xiv, 

 figs. 24 — 26), being more sharply pointed and laterally compressed, but in other 

 respects agree with E. multisegmentatus. 



The pygidium of the latter species has been compared with E. multiplicatus, 

 Salter, by the present writer, 1 and it may be remarked that the latter species 

 differs chiefly from these Girvan specimens by the longitudinal lineation of the 

 pleurae and by the different course and origin of the last pleurae. The last pair of 

 pleurae in E. multisegmentatus arises close to the tip of the axis instead of at the 

 16th axial ring, as Tornquist (loc. cit., 1884) shows in his figure of a Swedish 

 specimen. 



Collection. — Mrs. Gray. 



Horizons and Localities. — Whitehouse Group (M. Bala) : Shalloch Mill. 

 Drummuck Group (U. Bala) : Starfish Bed, Thraive Glen. 



Genus CYBELE, Loven. 



1. Cybele bellatula (Dalman), 1826. Plate XVI, figs. 14—17. 



1826. Calymene bellatula, Dalinan, K. Svensk. Vet. Akad. Handl., p. 228, pi. i, figs. 4a— d. 



1828. Calymene bellatula, Dalinan, Pahead., p. 36, pi. i, fig. 4. 



1830. Zeihus verrucosus, Pander, Beitr. z. Geogn. Eussl., p. 140, pi. ivc, fig. 4; pi. v, fig. 5. 



1845. Cybele bellatula, Loven, Ofv. K. Svensk. Vet. Akad. Forhandl., p. 110, pi. ii, fig. 3. 



1848. Zeihus verrucosus, Volborth, Verhandl. Miner, (resell. St. Petersb., p. 8, pi. i, figs. 5 — 7. 



1854. Cryptonymus bellatulus, Angelin, Pal. Scand., p. 3, pi. iv, figs. 1 — 3 ; and p. 89. 



1858. Zeihus verrucosus, Hoffmann, VerLandl. Miner. Gesell. St. Petersb., p. 32, pi. iii, fig. 4. 



1860. Cryijtonymus bellatulus, Eichwald, Leth. Ross., p. 1414. 



1860. Cryptonymus pwrallelus, Eichwald, ibid., p. 1417. 



1865. Cybele dentata, Kjerulf, Veiviser, p. 6. 



1 Reed, ' Geol. Mag.' [4], vol. viii (1901), p. 107; ibid. [5], vol. i (1904), p. 387, pi. xii, fig. 5. 



