Paleozoic Bivalved Entomostraca. 269 
to Bythocypris Phillipsiana; but the overlapping valve is 
the right instead of the left. The dorsal edge is elliptically 
arched, the ventral nearly straight, and the ends are neatly 
rounded, with one of them smaller than the other. 
Macrocypris Vinet, Jones, is also found in an Upper- 
Silurian (Wenlock) shale at Fréjel in Gothland. Ann. & 
Mag. Nat. Hist. June 1888, p. 396. 
II. Ponrocypris, G. O. Sars, 1865. 
(Ann. & Mag. Nat. Hist. March 1887, p. 182.) 
There appear to be three varieties of Pontocypris Mawti *, 
Jones, in the Silurian clay of Wisby. 
1. Pontocypris Mawii, Jones, var. breviata, nov. 
(Pl. XV. figs. 4a, 6, c.) 
Proportions :—L. 20. H.11. Th. 8. 
Shorter and rather thicker than the published type, but 
still somewhat compressed; hence appearing in side view 
irregularly subovate, like an orange-pip. It approaches very 
nearly in outline to the figure of the thick variety of P. 
Mawti ¢ from Fréjel (Wenlock shale), Gothland; but it is 
too high and blunt anteriorly and is much less convex on the 
sides. Its hinder extremity is slightly pinched, but not nearly 
so much as in Bythocypris caudalis (tigs. 2 and 3). 
2. Pontocypris Mawit, Jones, var. proxima, nov. 
(BI XV tgs. 5:a,.6;) 
Proportions :—L. 21. H.10. Th. 93. 
This is very similar to the type, but is proportionally 
thicker, that is, more convex, though still retaining a slight 
flattening on the sides (faces) of the valves, and the anterior 
slope is less steep. 
3. Pontocypris Mawii, Jones, var. divergens, nov. 
(Pl. XV. figs. 6a, 4, c.) 
Proportions:—L. 23. H.11. Th. 10. 
The carapace is here lengthened proportionally, the pos- 
terlor moiety being contracted above and below, so as to 
* Op. cit. BP: 182, 183, pl. iv. figs. 4, 6, and 7. 
+ Ann. & Mag. Nat. Hist. ser. 6, vol. i. p. 397, pl. xxii. fig. 3. 
