CHEIRURUS. 69 



muerones, and which is, at its upper portion, as broad as its pleurse, which have a wide, 

 straight base of articulation. The articular portion of the axis is also large. - 



Fig. 9 represents the outer granulated surface of the glabella. The furrows are not so 

 deep as in the cast (fig. 10) ; but the cheeks are equally scrobiculate, and more strongly so 

 than in our next species. 



Comparing with other species, we find, first, that the original C. clavifrons of Dalman 

 is, according to Angelin's figure, a species with a narrow glabella, somewhat gibbous at 

 the base, and with very broad and deep-fixed cheeks, with strong head-spines. The basal 

 lobes of the glabella are prominent and circular. The C. affinis of Angelin, which was 

 placed by Dalman with this, and seems by its shape to have been the actual species 

 intended by him, has a subclavate glabella, and also very forward, minute eyes. The 

 glabella of C. I u /nidus, Ang., a good deal resembles the large corresponding part in our 

 species ; but it differs essentially in not having the basal furrows complete, and the base 

 is very broad. C. gibbus, Ang., does not need a very close comparison, while the several 

 species arranged under Sphterexochus by Angelin must wait for more perfect materials 

 to decide their collocation. 



Localities. — Caradoc Slates and Limestones of Wales, Westmoreland, and Ireland. 

 In North Wales, — west of Bala Lake, Rhiwlas, &c. ; Corwen ; Cerrig-y-Druidion, &c. ; 

 Llanfyllin and other places in Montgomeryshire. In South Wales, — Sholes Hook, Haver- 

 fordwest ; abundant. Coniston, Westmoreland (M'Coy) ; Wexford and Chair of Kildare 

 (Mus. P. Geology, Woodw. Mus., &c). 



Ch. (Actinopeltis) octolobatus, M'Coy. PI. V, figs. 13, 14. 



? Calymene clavifrons, Balm. Vetensk. Akad. Handl., p. 75, 1826. 

 ? — — Loven. lb., p. 63, 1845. 



Sph.erexochus clavifrons, Salter. Memoirs Geol. Survey, vol. ii, pt. 1, pi. 7, fig. 



3, 1849. 

 Ceraurus octolobatus, M'Coy. Synopsis Toss. Woodw. Mus., pi. 1G, fig. 10, 1851. 

 Cheirurus — Salter. Decades Geol. Surv. 7, art. 2, p. 11, 1853. 



Cyrtometopus affinis, Angelin. Palseont. Suecica, t. xxxix, fig. 10 (1855, not 1854), 



(and quoting C. clavifrons of Dalman from the 

 originals in the Swedish Museum !) 



Ch. [Actinopeltis) minor, ovatus ; capite gibbo ; glabella oblongd nee ovatd ; genis 

 declivibus ; caudd 8-lobafd, brevi. Glabella convexissima tuberculata granulosa, antice 

 paullulum dilatata, postice sulcis completis lobos rotundos circumdantibus ; sulcis anti- 

 cis longis. Gena declives, externa parvula, fere perpendiculares, scrobiculafce ; oculis 

 minutis. Pleura spinosa. Cauda transversa bis quam longd latior, subplana, axe haud 



