HICKS MENEVIAN FOSSILS. 175 



the tips. Axis trilobed, the central lobe being largest and. pyramidal 

 in shape. The two lateral lobes triangular in shape. 



Tail of the same shape as the head, but more strongly margined. 

 The axis is large, and occupies more than a third of the width, reaches 

 backwards to within a short space of the posterior margin, and is 

 indented by three furrows on each side, each running obliquely 

 backwards from the centre, which is somewhat raised. 



Locality. — Menevian group : St. David's ; and near Dolgelly, 

 North Wales. 



Agnostus Eskeiggei, Hicks. PI. V. fig. 7. 



About ^ of an inch long. Head and tail each nearly circular in 

 form, highly convex, and with a smooth surface. Glabella indistinctly 

 marked by short lateral furrows. 



Thorax compressed, not so wide as the head. 



The axis of the tail is equal to about half of the width, nearly 

 circular in form, and exhibits no distinct furrows. 



Locality. — Menevian group : St. David's ; and near Dolgelly, 

 North Wales. 



Agnostits scuxalis, Salter. PI. Y. figs. 9-14. 

 Brit. Assoc. Eeport, 1865. 



This is the most plentiful species found in the Menevian group. 

 It seldom exceeds ^ an inch in length, though some of the specimens 

 are lengthened by pressure to rather over k, an inch. The general form 

 of the head and tail about two thirds of an oval, highly convex and 

 strongly trilobed, also strongly marginate. Glabella long and narrow, 

 occupying rather less than a third of the width of the head, and 

 tapering slightly ; it is divided by a transverse furrow into two lobes — ■ 

 an anterior of spheroidal shape, and a posterior elongated lobe which 

 supports a tolerably strongly marked tubercle ; a pair of triangular 

 lobes lie at the base of the glabella. The cheeks are covered with 

 small tubercles. 



Joints of the thorax strongly raised, axis trilobed, and pleurae 

 deeply grooved. 



Tail nearly of the same shape as the head ; axis equal to about 

 a third of the width. The axis is of about equal width for the upper 

 half, and then tapers to a sharp point from which a groove runs to the 

 posterior margin ; it is divided into three lobes, the anterior stretch- 

 ing as a narrow band across, the second transversely lozenge-shaped, 

 with a centrally raised tubercle, and the hinder one pyramidal. The 

 lateral lobes of the tail are disconnected by means of the terminal 

 fuiTow, and like the cheeks are covered with tubercles. 



Locality. — Menevian group : St. David's and near Maentwrog 

 and Dolgelly. 



Agnosttjs scakab^oides, Salter. PI. V. fig. 8. 



It is I inch long, Head and tail rounded to rather less than 

 two thirds of a circle, and surrounded by a narrow margin ; surface 

 depressed; head rather wider than long. Glabella pyramidal in 



