F. R. Cowper Reed—A New Species of Lichas. 399 
a complete furrow to the margin. This pleura is broad and triangular, 
and bears a submedian furrow on its surface curving round inwards 
towards the prolongation of the axial furrow, but dying out before 
reaching it. Half the side of the pygidium is formed by the margin 
from the second pleura to the point of the third pleura, and it is 
weakly sigmoidal, bending at first outwards and then inwards. The 
points of the third pair of pleurz are somewhat closely placed, and 
the margin between them is rather deeply emarginate. The post- 
axial piece is nearly as wide as the axis, is flattened, and bears no 
furrow. The tuberculation of the pygidium is similar to that of the 
thorax, but the tubercles show no regularity of distribution on the 
pleure, and the general surface of the lateral lobes seems to be also 
very finely granulose. 
The hypostome associated with this Zchas and most probably 
belonging to it has a strongly arched anterior outline and a deeply 
and broadly emarginate wide posterior border, but only the body is 
well preserved in any case. The body is rounded - subquadrate, 
moderately convex, rather broader than long; anteriorly it has 
a strongly arched outline, but its sides are subparallel, and its 
‘posterior end is abruptly truncated nearly at right angles and almost 
straight. The lateral middle furrows form a pair of simple broad, 
short, rather oblique notches in its sides at about two-thirds its length, 
and do not fork. 
Dimensions : 
2 Il. III. IV v: 
Length of whole individual ... one Le 30°00 — — — 
Length of head Bae vt noo.) Sa) 9-00 — — = 
Width of ditto Soe soo BOO 27°00 -= — — 
Width of glabella at pase Ba Sion CAL Sewanee ees — == 
Length of “thorax Be 13°25 ICs) 12°00 — ss 
Width of thoracic axis at front end.. 9:00 8:00 778 = = 
Length of pygidium .. Bs so SO 9-00 8:50 = 155 — 
Width of ditto - ek e000 20°00 16°00 26-0 == 
Width of axis of ditto ie ao | BOO 4:00 3°50 6-0 == 
Length of hypostome ae eo — — — 11-25 
Length of body of ditto tes — — — — 6°75 
A ffinities.—The general characters of the head-shield ally this form 
very closely to L. angusta, Beyr.,’ which Schmidt says is distinguished 
from L. deflexa,” Sjogr., by the glabella being less swollen and the 
median lobe less transversely expanded in front. The pygidium of 
LI. angusta, so far as it is known, agrees more with L. Hichwaldi, 
according to Schmidt, than with our specimens. The latter resemble 
in this part L. deflexa, which has the points of the-third pair of pleurz 
on the lateral lobes similarly projecting; but in ours these points are 
closer together, the whole pygidium is less transverse, the second pair 
of pleuree do not extend so far back, and the diagonal furrows of the 
third pair do not unite with the axial furrows. The hypostome of 
L. angusta seems to be practically identical, so far as ours is known. 
1 Schmidt: Rev. Ostbalt. Silur. Trilob., Abth. ii (1885), p. 108, t. iv, 
figs. 18-23. 
"2 Thid. , p- 101, t. iv, figs. 24-35. 
