Head strongly marginate, semicircular, and with a smooth surface ; angles produced into short spines, directed backwards. Glabella parabolic and convex, and indented by three very distinct lateral furrows which reach about one-third of the distance across. Cheeks wider than the glabella, and raised. Eyes situated at about one-third of the distance across from the glabella, and connected with the glabella by very strongly marked ocular ridges. The facial sutures run outwards and forwards above the eyes, and backwards below the eyes to the posterior margin, a little to the inner side of the spinous angles. Thorax consisting of fourteen segments ; the axis is convex and tapers gradually towards the tail. Pleurae less than half as long again as the rings of the axis, grooved deeply, and bent backwards from the fulcrum, which is situated about midway. Tail semicircular, with a tapering, strongly raised axis of four segments ; limb marked with four distinct ribs. This species approaches nearer to C. applanata than to any other Cambrian species, but is of larger size, has the eyes placed much nearer the glabella, has shorter pleurae, and a more strongly ribbed tail.
Locality. — A headland near Nun's Well, St. David's.
Conocoryphe solvensis, Hicks. Pl. XVI. fig. 8.
The head and a few thoracic segments only have been found ; but these are sufficient to mark a new species, resembling in some respects the Bohemian species C. coronata. The head is semicircular, tubercular all over, and strongly marginate. Glabella small, reaching less than two thirds of the distance forwards, narrow anteriorly, and indented by three lateral furrows. A strongly raised boss occupies the place anterior to the glabella, and reaches from it to the margin, but is separated at the base from the glabella by a deep furrow. Cheeks more strongly convex than the glabella, and about twice as wide ; the cheeks are wider than in C. coronata ; and it seems altogether a wider form.
Locality. — Road-side between Solva and Whitchurch, St. David's.
Microdiscus sculptus, Hicks. Pl. XVI. figs. 9 and 10.
Differs from Microdiscus punctatus, the only other species found in Britain, by having the lobes of the tail distinctly ribbed and not punctated ; is about equal to it in size.
Locality. — Headland near Nun's Well, St. David's.
Agnostus cambrensis, Hicks. Pl. XVI. figs. 11 and 12.
About one fourth of an inch long, and convex. Head longer than wide, and straight on the sides. Glabella occupying more than a third of the width, and divided at its anterior third by a transverse furrow. Tail nearly of the same shape as the head, with a wide axis centrally raised and indented by three furrows on each side.
Locality. — Headland near Nun's "Well, St. David's.
Theca antiqua, Hicks. Pl. XVI. fig. 13.
About 3/4 of an inch long ; surface not corrugated, and extremity
