320 Miffcellanea. 



width of the radiating ridges, which are also much less prominent ; 

 the smoothness of the mesial fold and width of the cardinal area 

 separate it from the S. convolufa (Phil.): and from the aS. 

 Rcemerianus (Kon.) it is known by its size, greater width, smooth 

 cardinal extremities, and flatter and wider lateral ridges. Length 

 1 inch I line, width 4 inches. 



From the hard schists of Lewin's Brook, N. S. Wales. 



Spirifera duodecimcostata (M'Coy). PI. XVII. figs. 2 & 3. 



Sp. Char. Transversely oval, or siibrhomboidal gibbose ; sides 

 rounded ; hinge-line shorter than the width of the shell ; cardinal 

 area wide, triangular, curved; mesial ridge prominent, deeply 

 divided by a mesial sulcus; mesial hollow wide, deep, defined 

 and sliowing a mesial ridge corresponding to the mesial sulcus of 

 the ridge of the ventral valve; five or six strong, subangular 

 simple ridges on each side of the mesial fold. 

 Length of dorsal valve 1 inch 3 lines, width 1 inch 9 lines. 



Not uncommon in the calcareous grit of Wollongong, and in the 



sandstone of Muree, N. S. Wales. 



Spirifera oviformis (M'Coy). PI. XIII. figs. 5 & 6- 

 Sp. Char. Longitudinally ovate, longer than wide ; hinge-line much 

 shorter than the width of the shell ; sides rounded, gibbose ; 

 mesial ridge large, rounded, divided by a deep farrow ; mesial 

 hollow very wide, flat, undefined ; three or four large, rounded 

 prominent ribs on each side of the mesial fold, rendered obscurely 

 nodulose by the obtuse concentric undulations of growth. 

 This is one of the very few Spirifer-a in v/hich the length exceeds 

 the Avidth, by which character it may be known from all the varieties 

 of the *S'. subradiala. The figures on the plate are from two 

 diflerent specimens. Length 2 inches 6 lines, wddth 2 inches 3 

 lines. 



Not uncommon in the sandstone of Barraba, N. S. Wales. 

 This species and the last belong to the subgenus Brachythyris 

 (M'Coy). 



Orthis striatula (Schlot.). 



On the most careful comparison I find nothing to distinguish the 

 Australian specimens from those so common in the Eifel and lower 

 Irish carboniferous shales. 



Abundant in the hard rock of Lewin's Brook, N, S. Wales. 



Orthis Australis (M'Coy). PI. XIII. figs. 4 & 4 a. 

 Sp. Char. Longitudinally obovate, very depressed, uniformlj'' convex, 

 length nearly equalling the width ; width greatest towards the 

 front margin, narrowing towards the hinge-line, which slightly 

 exceeds half the width of the shell ; sides and front margin 

 nearly straight, slightly convex ; surface with very numerous, 

 fine, nearly equal dichotomous striee radiating from the beak. 

 This is closely allied to the upper Devonian and lower carboni- 

 ferous fossil to wiiich Prof. Phillips restricts the name 0. ivterlineata, 

 and to the carboniferous O. Michelini (Lev.), {0. yiliaria, Phil.). 

 From the former it is distinguished by its narrow, longitudinally 

 obovate figure, and from the latter by its wider hinge-line and much 



