Carboniferous Trilobi/es. 83 



<jf Iwo on each side, are veiy small and neai'ly obsolete ; anterior lobe com- 

 posinu iicaily lialf of the glabella. Eyes lunate, not oblique, one-third as 

 long as the glabella, but not so prominent, situated less than their own 

 length in advance of the posterior margin of the cheeks near the glabella, 

 and about half their length from the lateral margins of the cheeks ; reticu- 

 lations very fine. Facial sutures intersecting tlie posterior margins of the 

 cheeks near the middle, and extending forwards from the anterior side of 

 each eye. at first close to the side of the glabella but soon curving outwards 

 and obliquely forward, so as to intersect the lateral margins nearly in front 

 of the middle of the eyes. 



"Thorax about one-third wider than long, distmctly trilobate; mesial 

 lobe prominent, about once and-a-half as wide as the lateral lobe, consisting, 

 <ipparently, of only 8 segments ; a little widest near the middle, and taper- 

 ing posteriorly ; segments not arching forw^ards, but strongly arched up- 

 wards, rather flattened . Lateral lobes depressed, somewhat flattened near 

 the mesial lobe, and rounding down rather distinctly to the lateral margins; 

 segments narrow on their upper edges, flattened in the direction of the axis, 

 and bent a little backwards below the knees, apparently rounded at the ex- 

 tremities. 



" Pygidiuni sub-semicircular, but a little rounded at the anterior lateral 

 angles ; about one-third wider than long, and as long as the glabella, exclu- 

 sive of the neck-segments and anterior marginal rim ; rather more broadly 

 lounded behind than the anterior margin of the glabella ; mesial lobe pro- 

 minent, about as wide anteriorly as the lateral lobes, and tapering back- 

 ward to an obtuse point within the margin, wiiere it ends rather abruptly 

 and is a little depressed, but not flattened ; consisting of nine or ten mode- 

 rately defined segments ; lateral lobes depressed below the mesial lobe, near 

 which they are slightly flattened, thence rounding to the margins ; each 

 •^vitli about seven rather faintly defined segments, of wiiich only the anterior 

 one is marked with a longitudinal furrow, all extending to within a short 

 distance of the margin, which seems to be slightly thickened. 



"Surface apparently nearly smooth, excepting the glabella, which is 

 covered with small, rather closely arranged granules, a row of very small 

 granules may also be seen by the aid of a magnifier, along the posterior 

 margin of the segments of the mesial lobe, both of the thorax and pygidiuni, 



"Entire length. 0.78 inch." * * * 



Locality and position : — Jersey County, Illinois; Kinderhook 

 Oroup of the Louver Carboniferous series. 



IV. PHILLIPSIA, Portlock, 1843. 



Plate 2, Figs. 4, 10, 11. 

 PMlUpsia, PoTtlock, 1843, Rep. Geol. Londonderry, etc., p. 305. 



Description. — General form oval ; glabella with nearly parallel sides, 

 anarked by either tw^o or three short lateral furrows ; the posterior angles 



