Vol. 67.] FROM THE PARADOXIDES BEDS OP COMLEY. 295 



spine, anterior border, and anterior marginal hollow are less strongly 

 developed. It would, moreover, appear to be a rather smaller form. 



Locality and horizon. — The little quarry at the northern 

 end of the Hill-House ridge ; from the coarse grits, both above and 

 below the, thick beds of compact grit. 



Pttchoparia (Liostractts) sp. indet. (PI. XXVI, figs. 3a-3c.) 



Another form which I refer to the subgenus is represented by 

 one imperfect external cast of a cranidium, preserved in a sandy 

 grit [1113]. It is principally remarkable for the great elevation 

 of the fixed cheeks, which are almost as high as the glabella, their 

 maximum altitude being situated towards the outer edge. 



Locality and horizon. — The upper section on the Shoot- 

 Rough lioad, Comley : from the main mass of the Shoot-Rough- 

 Iload Flags, about 8 feet below their upper limit. 



Pll'CHOPARIA (LlOSTRACTJS)? DT7BIA, sp. n0V. (PI. XXV, figs. 19«-21.) 



Several small heads in my collection from the same rock-bed as 

 Pt. (L.) pulcJiella, sp. no v., may possibly be young individuals, but 

 there are so many differences that I am not quite sure that they 

 belong even to the same genus. From Pt. (L.) jpulcliella they differ 

 in the following respects : — (1) The glabella is parallel-sided instead 

 of being truncate-conical; (2) there is no spine on the occipital ring; 

 (3) the eye-lobes are proportionately larger ; (4) the general con- 

 vexity is greater; (5) the space in front of the glabella is more 

 fully convex and, in consequence, the intramarginal hollow is narrow 

 and sharp. I think, therefore, that it is best to describe them in 

 full as a distinct species. 



Craxidium : Size. — Minute ; length = from 2^ to 3^ millimetres. 



General form. — Trapezoidal; features in high relief. 



General convexity. — High; about 1 : 3. 



Glabella. — Convex; parallel-sided; with rounded apex; dis- 

 tinct from the occipital ring ; rather more than half the total length 

 of the shield ; externally without farrows ; but one specimen, an 

 interior [366] (PI. XXV, fig. 21), shows two pairs of furrows directed 

 somewhat backwards. 



Occipital furrow. — Deeply impressed ; continuous. 



Occipital ring. — Convex; with the posterior margin curved 

 backwards, almost semicircularly. 



Axial furrows. — Very deeply impressed, both at the sides and 

 round the apex of the glabella. 



Fixed cheeks. — Nearly as wide as the glabella; transversely 

 convex ; continuous round the apex of the glabella, and of almost 

 equal elevation throughout ; widening out behind the eye-lobe, and 

 falling steeply into the groove of the postero-lateral border. 



Eye-lobe. — About a quarter of the length of the head-shield ; 



