BY JOHN MITCHKLL. 469 



of others assumed to belong to this species : suboblong, gi-aii- 

 ulated, longer than the p\^gidium, all the segmental ridges appear 

 to have borne tubercles; number of segments normal. Axis 

 prominent, ring-bases non-tuberculate, with a strong anterior 

 inclination centrally, ridges and valleys well defined, apparently 

 as wide as one side-lobe. Side-lobes strongly convex and steep 

 between the fulcra and margins, all parts densely granulated, 

 segments anteriorly angulate at the fulcra; mesial furrows wide, 

 ridges relatively narrow and faceted, and mildly thickened 

 posteriorly. 



Pygidivm very strongly convex, length to width approximately 

 2 : 3, granulated; axis prominent, evenly arched, anterior spread 

 about equal to the greatest width of one side-lobe, posteriorly 

 diminishing in width very gradually, and ending prominently 

 and bluntly a little short of the bordei-; number of rings thirteen, 

 and each bore a row of small tubercles quite conspicuous on 

 unweathered specimens; axial grooves wide and deep. Side, 

 lobes convex, consif^ting of eleven pairs of segments, the lidges 

 of each pair bearing rows of small tubercles varying from two or 

 three on the shorter, to eight or perhaps nine on the longer ones. 

 Border continuous, mildly thickened, convex and steep. 



Ohs. — At the outset, I admit that the pygidia here joined with 

 Mr. Etheridge's tj'pe-cephalon of the species may yet prove to 

 be a wrong conclusion; but should it happen so, T am inclined 

 to believe, too, that the heads (PI. li., figs. 1*2, 13) will also prove 

 not identical with the type one; but should that happen, I am 

 fully satisfied that these latter heads, and the tails here dealt 

 with, will prove to ijelong to the one species. The heads now 

 joined with the typical one possessing the very characteristic 

 frontal limb, cannot, for certain, in the absence of this limb, be 

 said to belong to the species. 



While completing the above description, the specimen No.712, 

 belonging to the Queensland Museum, Brisbane, is before me; 

 and the trilobite fossil remains on it consist of two pygidia, one 

 thorax and pygidium conjoined but incomplete, a fragmentary 

 head in intaglio, and a part of a free cheek. (On the same 

 specimen, occurs the tail of a Brachymetopus, the first recorded 



35 



