BY R. ETHERIDGE, JUNR., AND JOHN MITCHELL. 
495 
The largest cephalon that has come under observation indicates a 
length of three and a half to four inches for the whole body, 
therefore rivalling in size any of the P. fecundus or P. latifrons 
groups. From P. fecundus, Barr., it is clearly separated by the 
greater frontal expansion, and tumidity of the glabella, by the 
very distinct and deep glabella grooves, and the much smaller 
number of eyelets in the eyes. The presence of the glabella 
furrows at once separates it from such species as P. latifrons and 
P. rana. The above characters also separate it from our P. 
Crossleii and P. Sweeti, except that the eyes of P. latigenalis and P. 
Crossleii do not differ very widely. 
From P. fecundus, McCoy, (non Barr.), it is also distinguishable 
by the points above enumerated. 
To sum up, the distinguishing features of this species are its 
very tumid or inflated and rugose glabella, deep overhung glabella 
furrows, small number of lenses in the vertical rows of the eyes, 
which are supported on a distinct pedestal, and the wide cheeks. 
Loc. and Horizon. — ^Bowning, and Limestone Creek, near 
Bowning, Co. Harden. Middle Trilobite Bed, Bowning Series — % 
Wenlock. Coll. — Mitchell; and Geol. and Mining Mus., Dept. of 
Mines, Sydney. 
Phacops serratus, Foerste. 
(PI. xxxix., figs. 7 and 8; PI. XL., figs. 7 and 8 and 11.) 
P. serratus, Foerste, Bull. Sci. Lab. Denison Univ. 1888. iii. 
Sp. Char. — Body — Oblong oval. Head-shield or cephalon. — Nearly 
semicircular, a little wider than twice the length, highly tumid. Gla- 
bella, including neck ring, as wide as long, overhanging and tumid 
in front, very convex, surface highly granulate with fairly large 
and uniform granules, separated from rudimentar}^ limb in front 
by a very faint groove; sides straight, converging at angle of 60°; 
frontal furrows linear, widely Y-shaped, outer branches straight 
and passing into the axial grooves at the frontal angles, inner 
branches subfalcate, medial pair linear, subfalcate, and apparently 
not joining the axial furrows; frontal lobe large and subpenta- 
gonal, second lobes subtrapezoidal, small, third pair suboblong 
