CYPHASPIS JAMESONI. 27 



direct connection with the head-shield, but Mrs. Gray has recently discovered a 

 specimen with the pygidiura attached, though the thorax is missing. The characters 

 are the same as those which I described in the pygidia previously referred to it ; 

 but the new specimen shows an impression of the under surface, which is seen to 

 possess a concentrically striated doublure of uniform width, extending inwards as 

 far as the tip of the axis. On the upper portions of the pleural lobes within the 

 doublure there are traces of 5 — 6 pleurae, and the whole surface is finely reticulate. 

 Behind the axis the doublure seems to have been swollen into a low boss, and the 

 doublure itself is convex near the margin. The specimen is from the type-locality, 

 Ardmillan. The resemblance of the pygidium of this species to that of Stygina 

 latifrons, Portl., as figured by Wiman^ is striking and suggestive; but special 

 attention may be drawn to the many points of resemblance between B. 

 ardmillanensis and the Scandinavian Holometopns nitens, Wiman,- of the older 

 Ghasmops Limestone. 



Family Peoetid^. 



Genus CYPHASPIS, Burmeister. 

 Cyphaspis jamesoni, sp. nov. Plate IV, fig. 8. 



Specific Characters. — Head-shield parabolic, produced back at genal angles into 

 long points reaching to sixth thoracic ring. Glabella short, subquadrate, rather 

 more than half the length of head-shield and one-third its width, as broad as long, 

 widening at base into sub-oval basal lobes projecting slightly at sides and extending 

 nearly half length of glabella ; basal lobes marked off by fine weak furrows. Pre- 

 glabellar area gently convex, descending to flattened border. Eyes large, rather 

 more than half length of glabella, closely appressed to its sides, and posteriorly 

 nearly reaching to occipital furrow. Meso-occipital ring convex, arched gently 

 forwards in middle and at sides, where it is subnodular. Facial sutures bend 

 outwards in front of eyes to cut anterior margin of head-shield at about twice the 

 width of glabella apart. Free cheeks gently convex on inner portion, with rather 

 wide indefinite flattened border; genal angles produced back into long parallel 

 triangular flattened points reaching to sixth thoracic ring. Pleuro-occipital 

 segment well marked off by strong furrow continued back to tip of genal angles. 



Thorax of ten segments, with broad convex tapering axis, fully one-third width 

 of thorax; axial rings strong, rounded, with weak lateral swellings. Pleurae 

 strongly bent down at fulcrum, which is situated at less than half their length ; 

 surface of pleurae with wide oblique diagonal furrow. Pygidium small, semi-circular, 

 with convex, gently conical obtuse axis of 5 — 6 segments (imperfectly known). 



1 Wimau, 'Bull. Geol. Instit. Upsala,' uo. 10, vol. v, pt. 2 (1900), p 171, pi. v, fig. 18 only. 



2 Wimau, ibid., vol. viii (1907), p. 112, pi. vii, figs. 19, 20. 



