BY JOHN MITCHELL. 475 



Obs. — This is another of the pygidia described by Mr. Ether- 

 idge, Junr., {loc. cit.) but which he did not specifically name. 

 It resembles no other Australian Carboniferous form at all 

 closely; and, so far as I have been able to ascertain, it stands 

 apart from the pygidia of foreign species of the genera Phillipsia 

 and Griffithides. 



Loc. and Hor. — Greenhills, near Dungog; County Durham. 

 Carboniferous. 



Genus Griffithides Portlock, 1843. 



Geol. Report, Londonderry, &c., p. 3 10, 



The following is Portlock 's original description of the genus — 

 ''Cephalothorax semi-oval, longitudinal: glabella strongly marked 

 and gibbous, rounded in front, narrowed posteriorly into an ob- 

 solete neck with a furrow more or less distinct on each side. 

 Cheeks: triangular spaces very slightly convex. Wings either 

 ending in an angle posteriorly or prolonged backwards in a 

 tlattened spine. Eyes near the axis, not large, lunate, smoothC?). 

 The minute neck tubercle sometimes present. ' 



" Thorax. — The pleuripedes are compound, in number nine, or 

 with the neck segment ten." 



^^Fygidium. — Fully developed and strongly resembling that of 

 Phillipsia." 



General A. W. Vogdes {loc. cit.) gives the following brief 

 summary of the generic features of this genus: — 1. Glabella 

 short, tumid. 2. No short lateral furrows on the glabella. 3. 

 Basal lobes distinct. 4. Eyes small, placed close on the glabella, 

 reniform. 5. Axis of pygidium has 10 to 17 segments. 



Griffithides convexicaudatus, sp.nov. 

 (PI. xlvi., tig.l3; PI. xlviii., figs.1-3; PI. lii., figs.5, 6;. 

 Sp. Chars. — Complete form suboval with straight sides 

 Cephalon sub-semicircular, apparently finely granulated and 

 strongly inflated. Glabella subpyriform, tumid; basal furrows 

 faint; basal lobes relatively small; neck-furrow shallow, its lateral 

 extensions deeper, and communicating with the lateral furrows 

 of the free cheeks; neck-ring wider than the axial rings of the 



