Vol. 58. ] MR. F. RB. C, REED ON THE GENUS LICHAS. 77 
lobes composed of the fused second, third, and fourth lateral lobes. 
Occipital lobes are present in nearly all the sections. 
Section A. (Fig. 11.) 
In this section occipital lobes are present, and occasionally traces 
of the third lateral furrows are found crossing the tri-composite 
lobes. The posterior portion of the first lateral furrows may also 
be weak, and not form a regular continuation of the anterior portion. 
Fig. 11.—Lichas tricuspidatus, Beyr. (After Dames g Schmidt.) 
a 
[a from Zeitschr. Deutsch. Geol. Gesellsch. vol. xxix (1877) pl. xii, fig. 1 ; 
b from ‘ Rev. Ostbalt. Silur. Trilob.’ pt. ii, pl. ii, fig. 13.] 
The neck-ring is furnished with a posterior simple or bifurcated 
spine. The pygidium has an axis with two rings, and a broad 
post-axial piece. There are two complete pairs of pleurze on the 
lateral lobes, each with a pleural furrow and free point. The third 
pair of pleure is incompletely marked off from the post-axial piece, 
and has no pleural furrows ; the two free points of this pair may exist, 
or a single median point may replace them. 
Srction A. 
L. (Hoplolichas) tricuspidatus, Beyr. LL. conicotuberculatus, Nieszk., 
L. Plautini, Schm. LL. furcifer, Schm. 
L, longispinus, Schm. 
Section B. (Fig. 12, p. 78.) 
This section contains those forms in which the tri-composite 
lobes are complete, and marked out on their inner side by a regularly 
curved furrow. Occipital lobes are present. The pygidium has an 
axis with two rings, and a post-axial piece not defined by furrows 
posteriorly as in the last section. There are three pairs of pleure 
on the lateral lobes, each with a pleural furrow, but only the first 
two pairs of pleurz are complete and have free points, the third 
