PHACOPS. 41 



figured with it in the same work, will agree pretty well with Burmeister's figure of P. 

 conophthalmus, in his later and improved edition ;* much better than with Angelin's 

 figure, which surely represents the tail as too pointed, and he describes it with twelve lateral 

 ribs to the tail. We are still at sea about this species, but must accept Angelin's figure 

 as the type, as he has access to all the described Swedish species. I only describe 

 our own, and believe it will by and by constitute a new species. 



The head is transverse, semicircular but obtuse in front, and more than twice 

 as wide as long; very convex; granular, not tubercular; and with the wide glabella 

 occupying much more than one third of the head. It is nearly a right-angled triangle, 

 with the corners rounded off. The forehead-lobe is widely transverse, and considerably 

 overhangs the eyes. The upper lateral lobes are large, but not expanded forwards, only 

 behind, and rounded-trigonal; their transverse diameter fully equal to, if not greater 

 than the fore and aft measurement. The mid-lobes are quite obsolete, and the basal one 

 transverse-linear, and smaller than the neck-lobe. The cheeks are equilateral triangles, 

 very convex, and bear centrally the small eye, which is subtended by a much deeper 

 furrow than in P. macroura. The neck-furrow is strong, and continuous with the marginal 

 furrow, but the margin is in no part very broad. Head-angles short-spinous. 



The tail (which occurs in the same locality, and probably belongs to the same) is 

 transverse, " its length nine lines, against a breadth of fourteen lines ; the axis convex, of 

 ten segments, and about two thirds the width of the side-lobes in front ; abruptly 

 narrowed after the fifth segment. There are about eight lateral segments" (M'Coy). 

 The ribs are much arched, and reach quite to the margin ; strongly interlined throughout. 

 The surface of the tail is strongly punctate. 



This obtuse, short caudal portion is very like that figured by Burmeister in the Ray 

 edition of his work. It is more like the tail-piece of a large Calymene than a P/iacops. Not 

 having access to the Cambridge specimens at present, I had thought of leaving this and 

 some other doubtful species for a supplement, but prefer to present it, with other frag- 

 ments, in our Plate VI, and so complete what we at present know of this obscure 

 species. Collectors will do well to pay special attention to this fossil, as it is a charac- 

 teristic northern form. 



Locality. — Caradoc slates of Llansaintffraid, Glyn Ceiriog, south of Llangollen, 

 North Wales. Also at Acton Scott, in Shropshire (Mr. H. W. Edgell). 



I omit other localities, but one or the other of the above two species occur throughout 

 North Wales, at Llanfyllin, Llanwddyn, and Meifod, Montgomeryshire; Pwllheli and 

 Bettws-y-coed, Caernarvonshire. In South Wales, at Llandeilo. In Westmoreland, at 

 Coniston, Troutbeck, and Rother Bridge. In Clare and Kildare, Ireland. 



* Ray edition, 1846. He describes the tail as having nine lateral riba — the number present in a 

 specimen from Christiania in the Mus. Pract. Geology. 

 6 



