700 SILUUIAN TKILOBITES, 



and bending rapidly to and merging into the front margin, slightly 

 expanded in front; the first pair of lateral lobes in a rudi- 

 mentary form (tubercles merely) ; lateral portions distinctly 

 bilobed, median pair suboval, ^ ery tumid, aljout half the size of 

 the posterior pair, and very distinctly separated by the glabella 

 furrows which join the axial and false axial furrows ; false axial 

 furrows very distinct, particularly at their junctions with the 

 lateral furrows, passing into the neck furrow ; axial furrows dis- 

 tinct and intensely so as they join the neck furrow, faint across 

 the posterior margins. Fixed cheeks suboblong, tumid; genal 

 lobes ridged; ocular ridges or bands prominent, each bearing a 

 row of granules ; genal furrows distinct; triangular areas large 

 and flat. Free cheeks very tumid, granulated, borders thickened, 

 marginal furrows distinct and terminating at the front angles of 

 the glabella, the borders bear fourteen acicular spines exclusive of 

 the genal spines, which are also aciculai', strong, slightly falcate 

 and long, and bear the last two or three cheek spines ; facial 

 sutures anteriorly straight and nearly parallel with the axial 

 centre, posteriorly parallel with the lateral extensions of the fixed 

 cheeks. Neck furrow shallow generally, but deep at its junctions 

 with the axial furrows, its lateral extensions interrupted by the 

 tumid ends of the neck ring, thence moderately distinct across the 

 posterior borders of fixed cheeks. Keck or occipital ring strong, 

 intensely arched backwards, ends nodular, granulated, and central 

 tubercle present. Eyes prominent, of medium size, conoid and 

 faceted. 



Thorax. — Consists of nine segments, suboblong or subfusiform, 

 width equal to the combined length of itself and pygidiuiu, 

 exclusive of the spines; axis prominent, having two rows of dis- 

 tinct dorsal granules, rings arched backwards, ends nodular, 

 width equal to width of side lobes between the fulcrum and axial 

 furrows, which are faint; side lobes horizontal between axial 

 furrows and fulcra, thence moderately deflected, median ridges of 

 pleurje strong and prominent, and each at the fulcrum bears a 

 very distinct tubercle, forming a persistent row on each lobe, on 

 the deflected ends the ridges widen, and are produced into long 



