154 



Cardita delicatula, spec. nov. Plate ii., fig. 10. 



Shell roundly- oblong, rather depressed ; umbones anterior 

 oblique, incurved ; posterior margin roundly truncated. 



Surface ornamented with 2(3 compressed radial ribs, densely 

 beset with granules passing into scales on the posterior slope ; 

 interspaces a little w-ider than the ribs. Inner margins of 

 valves coarsely crenulated. 



Dimensions. — Length, 11 ; width, 10 ; thickness through 

 both valves, 6 millimetres. 



Localities. — Common in the calciferous sandrock of the Eiver 

 Murray Cliffs, near Morgan ; Muddy Creek ; Schnapper Point 



With the general form of C. gracilicostata this species is dis- 

 tinguished by its fewer and granular ribs. 



Cardita Tasmanica, spec. nov. Plate xii,, fig. 13. 



Shell thick, roundly oblong, rather depressed ; umbones pro- 

 minent, oblique, incurved ; anterior side very short. 



Surface ornamented with 22 thickish, elevated, densely cre- 

 nately-nodose, radiating ribs ; interspaces a little wider than 

 ribs, moderately concave, transversely wrinkled. Inner mar- 

 gin of valves coarsely crenulated. 



Dimensions. — Length, 16 ; width, 14 ; thickness through both 

 valves, 9 millimetres. 



Locality. — Table Cape I {B. M. Johnstoii) . 



This species comes very near C. delicatula, but it has fewer 

 ribs, which are thicker and coarsely ornamented ; it has much 

 resemblance to C. rotunda, Lea. of the Claiborne-Eocene, but 

 that species has thin, elevated, scaly ribs. 



Explain ATiON of Plates. 



IN'.B. — The figures are of the natural sizes, except when 

 otherwise stated. 



Plate II. 



1. Cardita trigonalis, Tate. Enlarged. 



2. Cardita Murrayana, Tate. 



3. Cardita spinulosa, Tate. 



4. Cardita scabrosa, Tate. E. Murray Cliffs. 



5. Cardita latissima, Tate. 



6. Cardita gracilicostata, T. Woods. 



7. Cardita polynema, Tate. 



8. Cardita gracilicostata, T. Woods. A young example. 



9. Mytilicardia curta, Tate. 



10. Cardita delicatula, Tate. E. Murray Cliffs. 



11. Cardita pecten, Tate. Enlarged. Muddy Creek. 



12. Mytilicardia alata, Tate. 



13. Cardita compacta, Tate. 



