1 12 
BULLETIN OF THE LABORATORIES 
of the lobe (for an extent corresponding to about two segments) not 
divided, rounded posteriorly, the segments nearest the thorax similar 
to the segments there found. The more posterior segments have their 
ends curved decidedly backward, so as to follow the general semi- 
circular arrangement of the articulations of the lateral lobes. Lateral 
lobes divided from the mesial lobe by a distinct, quite deep furrow, 
broadening posteriorly. Articulations about six.^ The anterior 
articulations together with the segments of the mesial lobe forming a 
semi-circular curve. The posterior articulations become less curved 
and take a more decidedly backward direction. The last pair of ar- 
ticulations in this way become almost parallel to one another and 
together with the posterior edge of the pygidium form a sort of box 
into which the unsegmented portion of the mesial lobe enters from 
above. The articulations of the lateral lobes are furrowed above 
along the middle, the furrows extending almost to the edge of the 
pygidiT_.m. 
Surface of the pygidia, and the head and thorax described above, 
finely granulated. 
Width of pygidium, 37 mm.; length, 25 mm.; width ofthe anterior end 
of the mesial lobe, 15 mm.; width at the beginning of the unseg- 
mented posterior portion, 6 mm. 
Locality a?td position. Allen’s and Soldiers’ Home Quarries, in the 
upper, shaly courses of the Clinton Group. 
GENUS LICHAS, Dalman. 
VIII. Lichas breviceps. Hall. 
{Hate XIII, -Figs. 26 a, t, c, d.) 
Glabella (Fig. 26 b) of one specimen convex. The middle lobe 
rounded in front, on each side suddenly and deeply incurved by the in- 
troduction of two lateral lobes, the sides almost parallel for a short 
distance posteriorly, then curving for a short distance outwards so as to 
meet the occipital furrow; at the point where the last curvature begins 
the posterior part of the lobe is 2.5 mm. broad, along the occipital fur- 
row, 5 mm.; the width of the lobe is exactly equal to its length. 
Lateral lobes sub-reniform, almost twice as long as wide, separated 
from the middle lobe by sharp grooves evenly curved except at the 
posterior end where 'the expansion of the posterior end of the middle 
lobe causes a slight irregularity of curvature; anteriorly the lateral 
