BRITISH FOSSILS. 



9 



shorter than the glabella of the head, and hyperbolic rather than 

 parabolic in outline ; its breadth at base is greater than the whole 

 length. A sharp sulcus surrounds the central lobe, which has two 

 pairs of furro ws faintly marked out ; the upper ones transverse and 

 reaching far inwards, the middle pair of furrows rather below the 

 middle. A prominent round tubercle ornaments the centre of the 

 lobe, of larger size than usual in the genus. The limb is very con- 

 vex, and the marginal rim is broader than that surrounding the 

 head ; it has a pair of strong short spines on its outer and lower 

 border, which are placed higher up than in A. McCoy ii and A. 

 princeps, before described. 



Affinities. — There is no trace in A. tardus (Barr. Boh. Trilob., 

 pi. 49) of the slight lateral indentation in the glabella, which indi- 

 cates the position of a furrow. Nor are there any traces in his 

 specimen of the lateral spines to the tail, any more than in the 

 allied Swedish form, A. lentiformis, Angelin. But the A. glabratus 

 of Angelin, a Caradoc form from Besstorp, in Yestrogothia, is far 

 more like, and if I might suppose that his artist had made the form 

 too elongate, and drawn the tail axis too large, I should consider it 

 identical. The body rings in his species are very cleaiiy shown 

 (and ours should be sought for). The second ring differs a good 

 deal from the anterior one. 



Localities and Geological Position^ — Haverfordwest, S. Wales ; 

 Bala and other localities in N. Wales; Shineton, near Cressage, 

 Shropshire, &c. ; Chair of Kildare, Ireland ; Penwhapple Burn, &c., 

 Girvan ; Ayrshire. 



Foreign. — Probably Yestrogothia (D.), as A. glabratus, Angelin. 



Section 4. — Phalacroma ? 



AGNOSTUS. — Sp. 



Plate I. Fm. 12. 



We have only the caudal shield of a species resembling the A . 

 nudus of Bej^rich (more like that species than any British one). 

 The central portion is but faintly marked out ; it is, however, smaller 

 in proportion to the limb than in the Bohemian species. 



The length of the pygidium is less than two lines. It is long- 

 semioval, the border concave, and is nearly as broad as the axis, 



