664 C. 6ALLAWAY ON A NEW AREA OF UPPER 



underside of the bead the vertical furrow on the epistome shows 

 distinctly through the cast. The labrum is imperfect, hut exhibits 

 a strong marginal groove and two small lateral furrows. 



"The body-rings have the axis as broad as the sides, and moderately 

 convex. The pleurae are flat as far as the fulcrum, truncate at their 

 ends, and have but a slight groove, which reaches only two thirds 

 of the length. The fulcrum is at one third in front, and less than 

 halfway out in the middle rings. 



" The caudal axis extends three fourths down the smooth tail, very 

 indistinctly marked above, but in some specimens crossed by several 

 faint rings, and is always prominent at the tip. 



" This has the characteristic facial suture of Isotelus ; but if its 

 labrum be like that of A. affinis (i. c. entire), a point Avhich is not 

 yet known, it may belong to quite a distinct subgenus." 



To this aceount, which very well suits our Shineton forms, I have 

 to add a description of the labrum. 



Labrum as broad as long, rounded on all sides, slightly indented 

 in front ; centre rather convex, with a strong furrow on each side 

 converging to nearly the front indentation ; just below the centre 

 a tubercle on each side, margined by a short deep furrow behind. 



The labrum (PI. XXIV. fig. 1), as Salter inferred from the imper- 

 fect material at his command, is not forked, a character which clearly 

 distinguishes this species from typical Asaphi ; and I propose for it 

 the subgeneric name of Asaphellus. Fragments indicate a size of 

 three inches by two. This makes the breadth greater than in Salter's 

 description, "three inches long and one and a half broad ;" but the 

 specimens from Portmadoc arc so greatly cleaved as to render the 

 measurement of proportions exceedingly difficult. 



From the Shineton Shales at Shineton. Very common. 



Platypeltis, subgen. nov., Callaway. 



Platypelhs, Callaway, Quart. Journ. Geol. Soc. vol. xxx. p. 190, 

 is 74. 



Oval, moderately convex ; axial furrows tapering gradually back- 

 wards from where they meet the facial suture in front of the eye to 

 two thirds the length of the tail ; head and thorax about equal in 

 length, tail shorter. 



Head with short cheek-spines, length two thirds the width ; eyes 

 placed near the margin, one third the length of the head, facets 

 small as in typical Asaphi ; facial suture forming three curves of 

 about equal length, cutting the front margin in front of the eye, and 

 the hinder margin at more than halfway from the axis ; glabella 

 one third of the width of the head behind, lobeless, axial furrows 

 well marked ; labrum (PL XXIV. fig. 2 a) entire, broadly rounded in 

 front, closely resembling the labrum of Asaphellus, but seemingly 

 destitute of the two furrows which converge from the side tubercles 

 towards the front. 



Thorax with well-marked axis equal in breadth to the pleurae ; 

 pleurae rounded at the ends, faceted, grooved to less than half their 



