670 SILURIAN TRILOBITES OF NEW SOUTH WALES, V., 



Ohs. — The subrectangular and steep-sided thorax, very pro- 

 minent thoracic and pygidial axes, acicular terminal of the tail- 

 axis, eleven pleural segments in the pygidium, widely expanded, 

 rounded and tumid glabella anteriorly, forward eye-lobes, and 

 strong drooping of the pygidium posteriorly, separate this species 

 from E. mitchelli, its nearest relative. When specimens of the 

 two are placed side by side, the differences become at once ap- 

 parent, and more particularly in that of the outline. In the 

 Australian type-species, this is broad-oval forwards, whereas 

 E. i-othwellcE is narrow-oval. Another marked difference is that 

 in E. roth^vellcE the axes of the thorax and pygidium diminish 

 gradually and regularly from the neck-ring to the pygidial 

 terminal, whereas in E. mitchelli the axis of the thorax is sub- 

 fusiform, and the last ring of the thorax is much wider than the 

 first ring of the pygidial axis, which narrows rapidly in the 

 distance between the first and third annulations, thence gradu- 

 ally becoming narrower and ending in a submucronate append- 

 age. Again, the entire body of E. mitchelli presents an appear- 

 ance of flattening, as compared with E. rothwellce. 



As regards the pygidium, in outline it resembles very much 

 that of E. etheridgei, but the latter usually has thirteen pleural 

 segments instead of the eleven normal in E. rothwelloi. 



Named after Miss Rothwell, Headmistress of the District 

 School, Lismore, who was associated with one of us as student 

 and assistant. 



Log. and flor.— Railway Cutting just west of Bowning Rail- 

 way Station, Parish Bowning, County Harden; Upper Trilobite 

 Bed, Bowning Series. Upper Silurian ( = 1Wenlock). 



EncrinurusC?) duntroonensis, sp.nov. 

 (Pl.lvi., figs.ll, 13.) 

 Sp. Chars. — Complete form unknown. Cephalon transversely 

 subelliptical, much wider than long, moderately inflated and 

 tuberculate. Glabella approximately one-third as long as the 

 width between the genal angles, elongately subpyriform, sides 

 subparallel, anterior portion or lobe bluntly rounded in front 

 and tumid, strongly arched transversely, sparsely granulate, four 



