BY R. ETHERIDGE, JUNR., AND JOHN MITCHELL. 
493 
Phacops latigenalis, sp.nov. 
(PL xxxix., figs. 3-6; PL xl., figs. 2-6 and 9.) 
Sp. Char. — Body. — Oblong ovate. Head-shield or cephalon. — 
Subsemicircular, but a little wider than twice the length. Glabella, 
including neck ring, wider than long, the proportion being about as 
4-3, highly tumid in large specimens, expanded transversely, 
slightly overhanging in front, and separated from the rudimentary 
limb by a fairly distinct groove which communicates with the axial 
furrows, strongly granulate, granules subcorneal, and nearly 
uniform in size, sometimes coalescing and forming ridges or 
wrinkles; glabella grooves very distinct, deep, and in large speci- 
mens the first and second pair are overhung by frontal and second 
lobes very decidedly, intercalary groove wide; second pair gently 
curved or falcate, and in mature decorticated specimens seem to 
communicate with the axial furrows; first pair widely Y-shaped, 
the inner branch being subfalcate, passing into the axial furrows 
at the front angles of the glabella; frontal lobes very large, 
occupying more than two-thirds of the glabella; second pair small, 
subdeltiform; third pair small and suboblong; intercalary ring 
nodular; axial grooves deep; neck furrow very deep and con- 
tinuing with equal distinctness across the side lobes to the inner 
edges of the borders of the free cheeks and thence faintly to the 
front of the eye, where it is interrupted by the lobe on which the 
eye rests; neck ring intensely arched, rather narrow, ends nodular; 
fixed cheeks small; genal lobes deltiform, arched, granular; 
palpebral lobes lunate, separated from genal lobes by shallow 
but distinct furrows, which continue posteriorly round and under 
the eyes, adding to the prominency of those organs ; anteriorly they 
pass into the axial grooves; free cheeks practically smooth, 
coalesced, extended towards the genal angles, border wide, thick, 
genal angles flattened, forming large triangular facets on which 
the first pleurae imbricate. Eyes half as long as greatest length of 
cheeks, slightly overhanging, subsemicardioid or lunate; perpen- 
dicular height small compared with that of most species of the 
