"Vol. 52.] FAUNA OF THE KEISLEY LIMESTONE. 435 



These characters necessitate, in my opinion, the creation of a 

 subgenus of Cyphaspis, which may appropriately be termed Torn- 

 quistia. Our Keisley form may aptly bear the specific name 

 Nicholsoni, in honour of its discoverer, Prof. H. A. Nicholson. 



Cyphaspis ? Harknessi, sp. n. (PL XXI. fig. 2.) 



Glabella conical, gently convex, elevated above cheeks, tapering 

 gradually towards its rounded anterior end, which apparently 

 reaches the front margin of the head-shield. A pair of incom- 

 pletely defined basal lobes is present. No other lobes or traces of 

 furrows on the glabella. The furrow which partially defines the 

 inner side of each basal lobe runs from the neck-farrow forward and 

 inward for a short distance as a faint groove, making an angle of 

 about 60° with the neck-furrow ; then it suddenly bends round at a 

 right angle to its previous course, and runs in a straight line out- 

 ward and forward with increased strength, to end abruptly in a 

 sort of pit before reaching the axal furrow. There is a similar 

 expansion and depression at the bend in its course. The basal lobes 

 thus marked off are subcircular in shape, nearly half as long as the 

 glabella, and about one-third of its basal width, gently convex, but 

 not rising above the rest of the glabella, though projecting slightly 

 on each side of it. Axal furrows distinct, but not deep. Neck-lobe 

 of medium width, separated from the glabella by a very strong neck- 

 furrow. Posterior part of fixed cheek triangular in shape, flattened, 

 and gently bent downward ; anterior wing imperfect, apparently of 

 similar shape, but smaller. The facial suture cuts the posterior 

 border of the head-shield at a distance from the axal furrow of less 

 than half the basal width of the glabella ; thence it runs forward and 

 inward with a gentle curvature towards the anterior end of the basal 

 lobe of the glabella. At this point, where the eye was situated, it 

 appears to curve away from the glabella with the concavity of the 

 curve forward, and cuts the front margin at some distance from the 

 axal furrow. Outline of head-shield only partially preserved, pro- 

 bably semicircular ; narrow rounded border visible. Whole surface 

 of head covered with tubercles of various sizes. 



Measurements. 



millim. 



Length of head-shield 125 



„ of glabella 100 



Width of do. at base 120 



„ ,, at anterior end 9*0 



Length of basal lobes of do 45 



Phillipsinella parabola, Barr. 



Two glabellas of this species, with portions of the fixed cheeks 

 attached, have been found. There are also in the Woodwardian 

 Museum two pygidia, which correspond very closely with those 

 ascribed to this trilobite by Linnarsson, who called it PhiUlpsia 1 



1 Linnarsson, ' Om Vestergotl. Cambr. och Silur. Aflagr.', K. svensk. Vet.- 

 Akad. Handl. toI. viii. (1869) no. 2, p. 72, pi. ii. fig. 32. 



