220 Mr. Salter on Palaozoic Fossils from South Africa. 



proportions of the head to the body in the smaller perfect specimens. It is much 

 less convex than the species last described ; it has larger eyes, and swelled lobes 

 to the glabella (figs. 10 & 11) ; and both the pleurse and tail had probably much 

 shorter spines. Head somewhat semicircular, rounded in front, with a small blunt 

 apiculus, and nearly twice as wide as long. The glabella is wider than the cheeks 

 and distinctly divided from them ; it is convex, wider in front ; the furrows are 

 radiating, and straight, compared with those of the last species ; the middle and 

 basal ones only arching a little towards each other. Posterior head-angles rounded. 

 Eyes large, conical (fig. 12), placed nearly on the middle of the cheeks, which are 

 pitted in a radiate fashion. 



The glabella is covered with small scattered granules (not shown in our figure), 

 mixed with larger ones on the forehead-lobe. 



Thorax granulose, gently convex, the axis about as wide as the pleurse, the 

 joints slightly tubercular at the sides, but not elevated in the middle. The 

 fulcrum is in the same position as in the last species, and the pleurse are pointed, 

 but do not curve down steeply. 



The tail is semicircular and but little convex ; the axis of five distinct and three 

 obscure ribs, rapidly conical and pointed, not blunt or prominent, at the apex. The 

 sides have six strong lateral furrows (including the articular one), distinctly inter- 

 lined ; but the strong furrows do not reach the margin. The edge is spinose, but 

 too imperfect for its characters to be ascertained. 



Localities. — In dark-coloured and greenish-grey schists and light-coloured softer 

 rocks at Gydow Pass ; and in ferruginous nodules at Gydow Pass and Leo Hoek. 



Phacops; sp. 



There are perhaps two more species of Phacops in Mr. Bain's collection. 



No. 1, represented by a caudal shield, is certainly distinct. The specimen is 

 short-triangular, and has a very prominent blunt axis, with seven distinct ribs, — 

 even nine in a large specimen. The sides slope rapidly away from it, and are 

 obscurely marked ; with about five side-ribs, faint in the cast, not sharp and 

 distinct as in P. Africanus. The axis seems to be as broad as in that species. 



Locality. — In black schist at Gydow Pass. 



No. 2. — Of the other species we have only one specimen, and that consisting 

 of the thorax only, which has the axis much narrower than the pleurse. 

 It is in a light-coloured argillaceous rock from Leo Hoek. 



No. 3. — A specimen, which may belong to one or other of these two species. 

 The head differs from that of P. Africanus in the following particulars : — 



It is longer in proportion to the width, and the glabella is blunt and rounded in 



