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



Pachydomus ovalis (M'Coy). PL XIV. fig. 4. 



Sp. Char. Transversely oval, length five-sixths of the width, com- 

 pressed, thickness rather more than two-thirds of the length ; 

 beaks tumid, nearest the anterior end ; anterior and posterior 

 ends oval, rounded, the latter obscurely angulated at end of 

 hinge-line ; ventral margin regularly convex ; surface marked 

 with thick, unequal, cord-like concentric striae; lunette deep 

 ovate ; ligament external, large. 



The anterior and posterior adductor impressions are large and 

 oval ; the impression of the retractor of the foot very small, lunate, 

 just over the anterior adductor ; pallial impression with a small 

 rounded sinus before joining the posterior adductor. Distin- 

 guished from the P. lavis (Sow.) by the coarse concentric linea- 

 tion of the surface. Length 1 inch 8 lines, width 2 inches. 

 Very common in the sandstone of Wollongong, N. S. Wales. 



Pachydomus ? pusillus (M'Coy). PL XVI. figs. 1 & 2. 



Sp. Char. Small, ovato-orbicular, width slightly exceeding the 

 length, globose, thickness four-fifths the length ; beaks very 

 large, tumid, much incurved into the anterior cordiform space, 

 which is unusually deep ; anterior side short, rounded ; poste- 

 rior end rounded ; ventral margin very convex ; ligament very 

 large, external ; muscular impressions large, anterior deep oval, 

 posterior impression shallow, lunate, pallial impression entire ; 

 shell thick, surface rough with strong concentric imbricating 

 lines of growth. 



This curious little species resembles an Isocardia, but from the 

 great size of the external ligament, thick shell and general habit, 

 I have placed it in the present genus, but not without doubt, from 

 its diminutive size and peculiar proportions. Length 10 lines, 

 width 11 lines. 



Common in the sandy schists of Wollongong, N. S. Wales. 



Cardinia (?) exilis (M'Coy). PL XV. fig. 1. 

 Sp. Char. Transversely ovate, compressed, cuneiform, slender, 

 twice as wide as long ; dorsal margin convex ; beaks small, one- 

 sixth of the width from the anterior end ; posterior end at- 

 tenuated, obtusely pointed ; anterior side small, rounded ; an- 

 terior half of the ventral margin convex, posterior half slightly 

 concave ; surface with strong irregular imbricating laminse of 

 growth and close intervening imbricating striae. 

 This reminds us of the Unio (Cardinia) acuta (Sow. sp.) of the 

 European coal-fields, but is distinguished by its greater thickness, 

 more clavate form and arched dorsal margin. The muscular and 

 pallial impressions correspond with those of the lias species of 



