600 SILURIAN TRILOBITES OF NEW SOUTH WALES, vi., 



We also refuse to accept Mr Chapman's substitution of Goldius 

 for Bronteas, believing the latter to be too deeply engraven in 

 paheontological literature for replacement by any other term, 

 even if possessing priority. 



]3ronteus mksExMBkinus,* sp.nov. 

 (Plate xxvi., fig. 7.) 



Sp. Chars. — Fi/gidiiim subsemicircular, sides rather straight 

 for two thirds of length; most tumid centrally, and becoming Hat 

 to slightly concave towards the border: articulating face straight, 

 forming the greatest pygidial width; surface tuberculated and 

 striated: axis dome-shaped, moderately tumid, wider than the 

 pleural lobes, articulating ring strong; coarsely and irregularly 

 tuberculate ; axial furrow faint, and not continuous behind ; 

 pleurse strongly ridged along the inner edges except in the case 

 of the median one, in which the ridge is central; ridges strongly 

 tuberculate, and most pronounced towards the middle of their 

 len^'th, disappearing just before the border is reached: the tirst 

 rib of each lobe and the medial one are straight, the others have 

 a gentle curve. 



Ql)g — The only other tuberculate pygidium of a Bronteiis oc- 

 curring in Australia, known to us, is that uf Broiiteus longi- 

 spinosus Mitchell, but it so widely differs from this one, that to 

 compare them is not necessary. This pygidium is also widely 

 separated from the typical Devonian Bronteus JiabeUifer, as well 

 as from all others known to us. 



Since writing the above, Mr. Chapman's description and figure 

 of i>. {Goldius) cresswelli have come under our notice {loc. cit., 

 ante). The two species are apparently so dissimilar, that a detail 

 of their relationship also appears unnecessary. We may point 

 out, however, that, in the text, Z>. {Goldm!<) cresstuelli is said to 

 have only six ribs on each side of the central one of the pygidium; 

 but his figure shows seven. Which is correct? 



Loc. and Hor. -Molong, Parish Bell, (Jounty Ashburnham: 

 limestone-beds adjacent to Molong. (IjUpper Silurian. 



* ixearjix/SpLi'O'i := southern. 



