BY R. KTHERIDGE, JUNE., AND JOHN MITCHELL. 495 



The largest cephalon that has come under observation indicates a 

 length of three 9.nd a half to four inches for the whole body, 

 therefore rivalling in size any of the P. fecundus or P. latifrons 

 groups. From P. fecunduti, 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. latijrons and 

 P. 7'ana. The above characters also sejDarate it from our P. 

 Crossleii and P. Sweeti, except that the eyes of P. latigenalis and P. 

 Crossleii do not diifer very widely. 



From P. fec'iLndus, McCoy, {71011 Barr.), it is also distinguishable 

 by the points above enumerated. 



To sum up, the distinguishing features of this species are its 

 ver}^ 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 — *? 

 AVenlock. CoU. — 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.) 

 /'. serrntns, Foerste, Bull. Sci. Lab. Denison Univ. 1888. iii. 

 Sp. Char. — 5or/y — 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 rudimentary 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 



