143 



•diameter, 10'5 ; sectional diameter of both valves, 6 milli- 

 metres. 



Locality. — Muddy Creek. 



This species has a very strong external resemblance to 

 Loripes leucoma, Turton, but is abruptly truncated posteriorly; 

 the surface is lamellaiely ridged (not striated), and there are 

 no radial striae ; the external ligament removes it generically. 



Lucina projecta, Tate. 



Reference. — Trans. Roy. Soc, S. Aust., for 1885, t. xii., fig. 6. 



Shell thin, obliquely ovate, roundly truncated behind, 

 broader with a rounded margin anteriorly ; moderately convex. 

 Lunule lanceolate, somewhat deeply depressed. The ornament 

 •consists of subacute close-set lirae. 



Dimensions. — Antero-posterior diameter, 16 ; umbo-ventral 

 diameter, 14 ; sectional diameter, 8 millimetres. 



Locality. — Muddy Creek (older beds). 



Lucina ara^a, spec. nov. Plate xix., fig. 9. 



Shell orbicular and somewhat oblique, moderately convex, 

 thin, subequilateral ; umbones acute, only a little elevated, in- 

 curved ; lunule small, shortly lanceolate, and slightly sunken. 

 Posterior-dorsal margin is short, straight, and rather sloping ; 

 the anterior-dorsal margin being longer, less oblique, and a 

 little concave in front of the umbo ; anterior and ventral mar- 

 gins broadly curved, whilst the posterior margin is roundly 

 truncate. Ligament groove on the post-dorsal margin elongate 

 and narrow. The right valve has two cardinal teeth, the front 

 one being small, lateral teeth absent. Margin of valve plain. 

 Surface ornamented with fine concentric striae. 



Dimensions. — Antero-posterior diameter, 8 ; umbo-ventral 

 diameter, 6 ; sectional diameter of right valve, 25 millimetres. 



Locality. — Oyster banks of the Aldinga Cliffs. 



Lucina affinis, spec. nov. Plate xviii., fig. 11. 



Shell subquadrately-rotund, moderately convex, subinequi- 

 lateral ; front-dorsal margin slightly concave, post-dorsal 

 margin longer and sloping ; posterior area slightly depressed, 

 which produces a short truncated extremity to the margin ; 

 umbones prominently incurved. Margin of valve minutely 

 crenulated. Left valve with two diverging cardinal teeth and 

 developed laterals ; ligamental groove on the hinder-dorsal 

 edge long and narrow. Surface ornamented with concentric 

 striae. 



This species is separable from L. arcea by its depressed pos- 

 terior area, crenulated margin of the valves, and the presence 

 of lateral teeth. It also bears an external resemblance to 



