SUPPLEMENT. 
52 7 
Oleinis vermontana (n. s ). 
General form elongate; the posterior extremity obtuse. Head semioval, 
twice as wide as long, the posterior angles produced in short acute 
spines. Eyes narrow elongate; the space from the centre of the head 
to the outer margin of the eye much greater than the cheek, and the 
distance from the anterior angle of the eye to the frontal margin less 
than the length of the eye. Glabella lobed : hypostoma broad oval. 
Thorax imperfect, preserving six articulations and part of the seventh; 
the middle lobe wider than the lateral ones. The third articulation is 
much broader towards and at its lateral margin, and is prolonged 
obliquely downwards in a sharp spine, which reaches below the seventh 
articulation : the lateral extremities of the other articulations produced 
in short acute spines. 
Olenus vermontana. 
Another fragment, which is apparently of the same species, preserves eleven 
articulations of the thorax and the pygidium. The upper articulations are imperfect 
at their extremities; the last one is bent abruptly downwards, and terminates in a 
long spine on each side reaching below the pygidium. Pygidium semioval; the axis 
marked by four annulations, the two upper of which are faintly indicated in the 
lateral lobes. 
This species differs from the preceding in its proportionally narrower form, the 
relative proportions of the parts of the head, and the short acute posterior spines. 
The comparative width of the middle and lateral lobes of the thorax is a very 
distinguishing feature. 
Geological position. In the shales of the upper part of the Hudson-river group. 
