Obscure glabella furrows. 
Thorax with 11 segments; pleurae not grooved; tips notched. 
Pygidium triangular; axis of many joints, 18-23-30; centre marked 
by a single row of nodes and terminating in a long caudal spine. 
Pleurae, 8-10-12. 
ENCRINURUS PUNCTATUS, Brunn. Plate I, figs. 1-18; Plate II, figs. 23-24. 
Range, Ordovician of England, Sweden, Norway and Russia, &c. 
Silurian of Gotland, Sweden. 
Description: ‘The general form ovate, nearly twice as long as wide. 
The head is bounded by a thick marginal border, which is narrow at the 
glabella and ornamented with two rows of tubercles. 
Glabella clavate and gibbous, overhanging with 3 indistinct lateral 
furrows; large frontal lobe. 
The facial sutures commence on the exterior margin of the head, just 
above the genal angles, and run in an oblique direction to the large 
pedunculated eyes, over their base, near the middle of the cheeks, then 
converge to the front of the glabella; they then turn suddenly, at an angle 
of 90 degrees, downward, and running parallel in a vertical direction to 
the marginal edge, which they cut, and converging, combine into a rostal 
suture. 
The fixed cheeks are triangular, and separated in front by the verti- 
cal suture, convex and tumid. 
Free cheeks are prolonged at their genal angles into spines. 
The occipital furrow is continuous; occipital ring broadest in the 
centre, which is smooth, but has a node at each extremity. 
Hypostoma ovate, obscurely granulated, surrounded by a sinuated 
margin, connected by its pointed end with the head. ‘T‘he wings are short 
and triangularly pointed. A furrow runs from each side up to one-third 
part of its length, which runs vertical, and its end not visible in the pos- 
terior thickened part, a small, obtuse continuation is seen. 
Thorax with 11 segments. Pleurae without grooves, notched at 
their ends, but not spined; surface tuberculated. ‘The axial joints are 
somewhat narrower than the pleurae. Spines occur on the 7, Oo, Aid 16 
axis joints. 
Pygidium triangular, terminating in a caudal spine, the axis tapering 
posteriorly to an acute end, which has from 23-30 distinct side notches; 
the centre is smooth, with 7 prominent nodes: between the I—3 nodes 2 
notches appear; the 3-4 nodes have 4 notches; 4-5 nodes, 5 notches; 
6-7 nodes, 5 or 6 notches appear. 
The numerical arrangement of these nodes is not inviolable, 
Pleurae 8, with a central row of tubercles. 
