151 



Cardita trigonalis, spec. nov. PL ii., fig. 1. 



Shell triangular, moderately convex ; Tinibones elevated, 

 sliglitly oblique, incurved, anterior ; posterior^margin inclined, 

 making with the slightly arched ventral margin a roundly 

 acute angle ; anterior side rounded ; dorsally excavated. Sur- 

 face ornamented with 15 crenately-nodulose, rounded, radiating 

 ribs, the interspaces wider than the ribs with transverse thick 

 lirse. Inner margin o£ valves coarsely crenulated. 



Dimensions. — Length, 7 ; width, 6"5 millimetres. 



Locality/. — Oyster banks, Blanche Point, Aldinga Bay, 



Cardita pecten, spec. nov. Plate ii., fig. 11. 



Shell ovately triangular, transverse, rather depressed, regu- 

 larly convex, except the flattened posterior slope ; umbones 

 small, acute, antemedian, directed forwards ; anterior margin 

 rounded, posterior obliquely truncated. Inner margin of 

 valves coarsely crenulated. Surface ornamented with 22 

 narrow, compressed, crenately-granose, radial ribs ; interspaces 

 flat, wider than the ribs, 



Dimensions. — Length, 6*5 ; width, 2 ; length from umbo to 

 posterior angle, 6 5 ; thickness through both valves, 3 milli- 

 metres. 



Localities. — Muddy Creek ; Oyster-beds, North-"West Bend 

 of the Eiver Murray. 



Cardita compacta, spec. nov. Plate ii., fig. 13. 



Shell minute, rotund, subglobose, subequilateral ; umbones 

 prominent, obtuse, incurved, approximate. Surface ornamented 

 with 24 crenately-granose ribs separated by linear interspaces. 

 Inner margin of valves crenately-serrated. 



Dimensions. — Length, 5 ; width, 4'5 ; thickness through both 

 valves, 3 '5 millimetres, 



Locality. — Muddy Creek. 



This little shell resembles in ornamentation G. scalaris. 

 Sow., recent north-west coast of America, and fossil in the 

 English Crags ; and G. amahilis, Deshayes, living off the coast 

 of Tasmania, from both of which it differs in shape. It has 

 some affinity to G. parva, Lea of the Claiborne-Eocene. 



Cardita Murrayana, spec. nov. Plate ii., fig. 2. 



Shell ovate-quadrate, moderately inflated, inequilateral ; 

 umbo anterior, broad, oblique, incurved ; posterior side pro- 

 duced and flattened ; radiately ribbed. Eibs 20, broad, 

 rounded, elevated, crenulated; interspaces concave, about as 

 wide as the ribs. 



Dimensions. — Length, 35 ; width, 29 ; thickness through both 



