BY R. ETHERIDGE, JUNR.^ AND JOHN MITCHELL. 665 



Encrinurus silverdalensis, sp.n(a\ 

 (Pl.liv., fig.ll; Pl.lv., figs.4,9; Pl.lvL, figs.4,5,6, 14; Pl.lvii.,figs.3, 



10.) 



Sp. Char. — General form suboval. Cephalo7i subsemicircular, 

 and therefore approximately half as long as wide, moderately 

 inflated, densely tuberculate, tubercles variable in size, many 

 very large, conical, and all microscopically granulate. Glabella 

 separated, pyriform, tubercles in oblique rows or quincuncially 

 arranged, the large ones along the axial grooves somewhat 

 flattened. Neck-furrow narrow and inconspicuous, its lateral 

 extension across the fixed cheeks also narrow but deejD. Neck- 

 ring strong, wide, and moderately arched. Fixed cheeks moder- 

 ately inflated, bearing tubercles similar to those of the glabella 

 and arranged similarly; posterior border (extension of neck-ring) 

 narrow, but strong; genal angles rounded, thickened, and bear- 

 ing a few irregularly arranged tubercles. Free cheeks large, 

 especially so are those portions inside of the axial grooves, and 

 rest on the glabella front; tuberculated in a similar way to that 

 of the glabella, border wide, bearing one row of large, rather flat 

 tubercles along its inner border, and another row of smaller and 

 less regularly arranged ones along the outer margin; on both 

 inward and outward portions above the furrow the tubercles are 

 arranged in three more or less regular rows. Axial grooves join 

 the outward or lateral cheek-furrows, and also trend inward and 

 obliquely downward along the inner or frontal portions of the 

 cheek, passing out in front with the facial sutures. Eyes pedun- 

 culate, convex or subconical, peduncles surrounded by incon- 

 spicuous sulci. Facial sutures are of the usual generic type. 



Thorax almost rectangular, about two-thirds as long as wide, 

 microscopically granulate. Axis tapering almost imperceptibly 

 posteriorly, the last annulation being much stronger and wider 

 than first one of pygidial axis, annulations not tuberculate at 

 their bases but somewhat thickened ; pleur?c only moderately 

 geniculate. 



Pygidium large, widely triangular, much wider than long, and 

 longer than the thorax, granulated in a similar way to that of the 



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