BY R. KTHKRIDGE, .TUN'R., AND .TOHN MITCHRLL. 497 



ing very gradually posteriorly; pleurte flat, extremity of each 

 segment sharply depressed, free and claw-like. 



Pygidiuin exceedingly small, the largest that has come und^r 

 our notice being not more than 1| mm. in length, and 2.^, mm. 

 wide; axis distinct, hut not quite reaching the margin, two rings 

 present, side-lobes with three pleurie in adult specimens. 



Obs — This fossil very closely resembles Harpes uvfjnhi, and it 

 was with some degree of hesitation that we decided to give it 

 full specific rank. The features on which we rely to justify this 

 course are — (1) the thoracic somites of our species, in any of the 

 numerous specimens which have come under our notice, have 

 not exceeded twenty-two; (2) the relatively small size of the 

 glabella; (3) the greater length of the horns of the limb or border, 

 and their extension, in specimens of those which had not readied 

 maturity, beyond the end of the pygidium, and approximately 

 to the end of the thorax in those which had reached that con- 

 dition; (4) in our species, a sulcus joins each eye with the axial 

 furrow, but, in IIa> pes uuyula, a ridge is said to serve this pur- 

 pose; (o) the arching of the glabella is low and convex. The 

 largest specimens just exceed an inch in length, with a width of 

 thirteen-sixteenths of an inch. 



Loc. and //or. —Bo wn ing Creek, Parish Bowning, County 

 Harden: Lower Trilobite Bed. Upper Silurian. 



Cehatocephala Warder, 1838. 

 (See Proc. Linn. Soc. N. S. Wales, 1896, xxi., Pt.4, p. 707). 



Subgenus Bounyongia,"* s y.iiov. 

 The trilobite which serves us for the type of this subgenus 

 differs from others known to us in having a pair of cephalic 

 spines originating on the glabella in front of the neck-ring, and 

 it is this feature on which we found the subgenus. It may also 

 be noted that the eyes are apparently pedunculate, overhanging 

 the cheeks somewhat, and directed outwards at an angle of about 

 45°. 



* Bounyoiig is the Aborigines' name of Bowning. 



