0 
SILURIAN 
it from I. crassicauda, of Sweden, a species otherwise not un¬ 
like it. 
Localities .—Chorhoti Pass; one figured specimen, fig. 10, 
in a pisolitic iron ore. Gunesgunga ? (A similar iron ore is 
found in British Lower Silurian rocks, Carnarvonshire.) Fig. 
11, Milam Glacier. (Nos. 926, 1737, 1739, 1754.) 
4. CHEIRURUS MITIS. 
Plate 1, figs. 14—18. 
C. capite convexo. Glabella valde distincta, oblonga, antice paullo 
projecta, lobo frontali modieo, alter is vix latiori, 3 glabelloe longitudi- 
nem aequante. Sulci superiores et medii recti, breves, minime arcuati, 
trans 3 glabellax tautuxn exarati; basiles recurvi, lobos rotundos, late 
intervallo sejunctos, includentes ; genre valde scrobiculatse, profunde 
marginatse, sulco contmuo. 
Head nearly semicircular, convex, the glabella very distinct 
from the cheeks, oblong and parallel-sided, rounded and pro¬ 
jecting a little in front. It is strongly lobed,—the frontal 
lobe nearly a semicircle, very little wider than the rest, and 
occupying only one-tliird the length of the glabella. The 
upper and middle furrows are direct, short, very little arched, 
and reach but one-third across. The lower are very strong’ 
and recurved, and they mark out a pair of spherico-triangular 
lobes, leaving a wide interspace, on which a projecting 
tubercle is placed. Cheeks strongly scrobiculate, and deeply 
margined, the furrow continuous at the angle, which is spi¬ 
nous. Eyes nearly central, very large and prominent, showing 
lenses (fig. 16#) under a magnifier. 
The general appearance is much like that of C. speciosus , 
C. bimucronatus , C. insignia 3 Barr., &c., from all of which 
differences of proportion distinguish it. C. Quenstedti and 
C. Beyrichi, of Barrande, have also some resemblance, and if 
the caudal shield (fig. 18), which is found in company with our 
fossil, belong to it—as is most probable—the last-named 
species is the nearest ally. 
