234 Mr. F. M'Coy on the Fossil Botany and Zoology 



Spirifera duodecimcostaia (M'Coy). PL XVII. figs. 2 & 3. 



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

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

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

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

 denned, and showing a mesial ridge corresponding to the me- 

 sial 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, gib- 

 bose ; mesial ridge large, rounded, divided by a deep furrow ; 

 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 undu- 

 lations of growth. 



This is one of the very few Spirifers in which the length ex- 

 ceeds the width, by which character it may be known from all 

 the varieties of the S. subradiata. The figures on the plate are 

 from two different specimens. Length 2 inches 6 lines, width 

 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). PL XIII. figs. 4 & 4 a. 



Sp. Char. Longitudinally obovate, very depressed, uniformly con- 

 vex, 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 strise radiating from 

 the beak. 



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

 niferous fossil to which Prof. Phillips restricts the name O. inter- 



