67 



Genus Dionide, Barrande. 



D ? PERPLEXA, n. sp. — Head short, crescentiform, broadly and uniformly 

 rounded in front and backwards to the tips of the spines ; posterior margin 

 deeply and uniformly concave. The posterior angles of the head are pro- 

 duced backwards and gradually taper to a point, the whole having the form 

 of a perfect crescent. The dorsal furrows are distant from each other a 

 little more than one-fourth the width of the head on a line drawn across at 

 the neck segment. They converge inwardly so that at the neck furrow 

 they are one-third nearer than they are at the margin. Neck segment 

 rather large, strongly elevated at the margin and sloping down into the 

 neck furrow which is angular in the bottom and has a deep pit at each 

 extremity in the dorsal furrow. From each of these pits a shghtly impres- 

 sed line runs forwards and may be a continuation of the dorsal furrow. In 

 front of the pits there is a pair of tubercles resembling glabella lobes. In 

 front of these another pair of deep pits. The front of the head is crushed 

 in the only specimen collected. Just outside of the tubercles above men- 

 tioned there is an elevated tubercle on each side, probably the bases of the 

 eyes. Length of the head from the neck segment to the front margin about 

 3 lines ; length from the front margin to a line drawn across the tips of the 

 spines, 5 lines ; width between the tips of the spines 8 lines ; width at the 

 neck segment 1^ lines ; distance between the dorsal furrows at the poste- 

 rior margin 2 lines ; distance between the supposed eyes 3 lines ; from the 

 centres of the supposed eyes to the posterior margin 1^ lines. The Jum- 

 pers ; Div. 4, A. G. J. Richardson. 



The surface seems to be smooth with the exception of a few tubercles 

 on the spines. 



This trilobite may belong to some other geniis, but as it resembles (ex- 

 cept the eyes) Dionide, I shall place it in that group provisionally until 

 better specimens can be procured. 



Genus Beyrichia, McCoy. 



In the following description the widest extremity of the fossil is regarded 

 as being posterior. 



B. DECORA, n. sp. — Carapace valves small, semi-ovate ; anterior margin 

 for about half its length nearly straight and usually forming a right angle 

 with the hinge line ; then rounded ofiF to the ventral margin which is 

 straightish or gently convex in the middle half ; posterior margin forming 

 an obtuse angle with the hinge hue and straight in the upper third, then 

 rounded off to the ventral margin. Bight valve with a very convex ovate 

 tubercle in the lower posterior angle extending from the ventral margin 

 slightly more than half way to the hinge line ; the space between it and 



