126 BULLETIN OF THE LABORATORIES 



observed in ours; indeed it suggests in this our first species, but the 

 anterior of the glabella is not round; the drawing evidently leaves 

 much to be desired) , and the greater distance of the eye from both 

 dorsal and occipital furrows. 



Phacops serratus, sp. n. 



{Plate XIII, Fig. I.) 



Head with semi-circular outline, almost twice as broad as long. 

 Anterior lobes of the glabella equalling eight-elevenths of thcf length of 

 the head; its anterior margin, instead of being regularly rounded as is 

 usual in most species of Phacops, is rounded most at the middle of its 

 outline and at its junction with the dorsal furrow, giving the interme- 

 diate outline on each side a somewhat compressed appearance. The 

 curvature of the sides of the glabella is small, they converge posteriorly 

 and form an angle of about seventy five degrees with each other. 

 With the exception of a faint median elevation the surface is quite flat, 

 above bending rather abruptly into the dorsal furrows and at the anter- 

 for margin even becoming incurved. The specimen is slightly 

 exfoliated so that it is mipossible to say if there were any grooves on its 

 surface, but if so they must have been rather inconspicuous. It is 

 covered however with low small tubercles. This lobe of the glabella 

 is defined posteriorly by a furrow which is quite marked at the sides, 

 but toward the middle it becomes very shallow forming a sort of axis, 

 and curving more or less forwards. This furrow cuts off from the 

 remainder of the glabella two small posterior lobes, at either side con- 

 siderably depressed below the general level of the glabella and 

 terminated with a small knob, posteriorly it is defined by the well 

 marked occipital furrow. The occipital ring is very broadly subtrian- 

 gular and is terminated with a distinct, short, pointed projection, 

 which repeats itself on all the segments of the axial lobes of the thorax, 

 gradually becoming indistinct, and vanishing soon after reaching the 

 first ring of the axial lobe ot the pygidium. The eye has a reniform 

 outline and extends from a short distance behind the point of greatest 

 width of the glabella to within a short distance of the continuation of 

 the occij^ital furrow. The palpebral lobe is strongly defined by a very 

 distinct furrow which also outlines the posterior parts of the eye. 



