CHEIRURUS OCTOLOBATUS. 1 II 



Horizon and Localities. — Stinchar Limestone Group (Llandeilo) : Craighead; 

 Minuntion. P Balclatcbie Group (Llandeilo): Balclatchie Conglomerate. 



2 a. Cheirurus gelasinosus (Portlock), var. Plate XVIII, fig. 7. 



Description. — There is a small glabella from Balclatchie in the Museum of 

 Practical Geology Avhicli is seen to differ from 0. gelasinosus, Portlock, in several 

 particulars when closely examined. The glabella is subquadrate in shape, 

 nearly as wide as long, and slightly expanding towards the front ; the sides are 

 nearly parallel. There are three pairs of lateral furrows, all rather long and 

 extending more than one third of the distance across the glabella. The first pair 

 is very far forward, starting from the anterior lateral angles and sloping backwards 

 obliquely ; the second pair is at the middle of the glabella, and the furrows are 

 straight and horizontal ; the third pair is about half way between the second pair 

 and the occipital furrow, and the furrows are oblique and curved, almost enclosing 

 the triangular basal lobes. The occipital segment is narrower than the lateral 

 lobes, and bears a median tubercle. The axial furrows are deep, straight, and 

 nearly parallel. There is a narrow, rounded, frontal border before the glabella. 

 The surface of the glabella is evenly granulated, but not tuberculated. 



Dimensions. — 



Length of glabella . . . 10*0 mm. 



Width „ ... 8-0 „ 



Remarks. — This form differs from C. gelasinosus in the granulated, non- 

 tuberculated surface, the more forward position of the first lateral furrows, the 

 different directions of the three pairs of lateral furrows, and the narrower neck- 

 ring. It is certainly distinct from the Craighead type of C. gelasinosus, and the 

 non-parallelism of the lateral furrows marks it off from Portlock's Tyrone examples. 



Collection. — Museum of Practical Geology. 



Horizon and Locality. — Balclatchie Group (Llandeilo) : Balclatchie. 



Cheirurus (Cyrtometopus) octolobatus (M'Coy), 1849. Plate XVIII, figs. 



8—11. 



1849 



fig 

 1849 



Sphierexochus juvenis (e. p.), Salter, Mem. Geol. Surv., vol. ii, pt, i, p. 344, pi. vii, fig. 3b (non 

 1, la, 2, 3, 3a). 



Ceraurus octolobatus, M'Coy, Ann. Mag. Nat. Hist. [2], vol. iv, p. 407. 

 1851. Ceraurus octolobatus, M'Coy, Synops. Pal. Foss. Woodw. Mus., p. 154, pi. i o, fig. 10. 



1853. Cheirurus octolobatus, Salter, Mem. Geol. Suiv., dec. vii, art. 2, p. 11. 



1854. Ceraw-us octolobatus, M'Coy, Contrib. Brit. Pal., p. 146. 

 Cheirurus (Actinopeltis) octolobatus, Salter, Mon. Erit. Trilob., p. 69, pi. v, figB. 13, 14. 



1804. 



