716 SILURIAN TKILOBITES, 



Acidaspis loi/gispinis, Mitchell, Proc. Linn. Soc. oST.S. Wales, 

 1888, iii. (2), Pt. 2, p. 398, 1. 16, figs. 7-12. 

 Sp. Char. — Bodij oval, suboblong. Cephcdic shield or cephalon 

 only moderately tumid, and distinctly but sparsely granulated. 

 Glabella with the central lobe suboblong, very moderately arched, 

 and sloping gradually into the neck furrow and to the front margin, 

 front angles modei^ately expanded and bearing distinct tubercles; 

 three pairs of side lobes pi-esent, first very small, depressed, 

 second and basal pair large, subcircular, moderately tumid and 

 nearly of equal size; false furrows distinct and very wide; glabella 

 furrows — first pair faint, second pair deep and distinct, uniting 

 the axial and false furrows, basal pair very wide and shallow, 

 also uniting the axial and false furrows; axial furrows ver}' faint 

 anteriorly and moderately distinct posteriorly; genal lobes small, 

 distinctly and regularly granulated, prominent posteriorly, incon- 

 spicuous anteriorly; palpebral furrows distinct anteriorly; ocular 

 ridges prominent, filamentous, and distinctly granulated; lateral 

 extensions of the fixed cheeks robust, having very prominently 

 thickened borders. Facial sutures anteriorly straight, and making 

 angles of 120° degrees with the front margin, posteiiorly straight, 

 passing out at the genal angles, and making angles of 35° with 

 the posterior borders of the cephalon. Eyes prominent, conoid, 

 numerously and minutely faceted. Free cheeks of moderate size, 

 borders very wide, moderately tumid, lobe-like, bearing several 

 rows of granules, one of which is rather distinct, margins very 

 minutely spinate, spines only visible under a lens, genal spines 

 very long, strong, arcuate, and diverging from the thorax ; 

 triangular ai-ea small. Neck furrow very wide and shallow 

 centrally, but deep behind the basal glabella lobes, very faint 

 over the genal lobe ridges, thence distinct to the genal angles^ 

 branches distinct. Neck ring very moderately arched, wide, 

 surmounted centrally by a very prominent granule; nodules or 

 side lobes distinct, separated from central portion by the axial 

 extensions of the neck furrow; occipital spines very robust and 

 long, arching, the ends divergent and apparently reaching to the 

 extremity of the pygidium. 



