70 



up in Streaky and Fowler's Bays. Large living examples cast 

 up at Rosetta Head, Encounter Bay (B. H. Pulleine!). 



This new species has much the shape of O. Preissii, IMenke, 

 as figured by Reeve, from which it differs by being wider be- 

 hind, with a well-defined posterior slope, and more convex ; 

 whilst the ribs are narrow, elevated, and more numerous. The 

 proportion of the measurements of C. JPreissii corresponding 

 with those given above for C. rosulenta is 100 : 75 : 50. C. rosu- 

 lenta makes a near approach to C. scabrosa, mihi, of the Old 

 Tertiary of South Australia and Victoria, but has fewer ribs, 

 and has not the arched dorsal line of that species. 



Gardita obliquissima, spec. nov. Plate v., fig. 9. 



Shell minute, very oblique and inequilateral, thick, white 

 or pale rose colour. Anterior side much larger than the pos- 

 terior, produced in frout, pyriform ; posterior side very narrow, 

 abruptly sloping from an angulation extending from the umbo 

 to the post- ventral margin : the whole surface is sculptured 

 with distant, regular, somewhat wavy concentric grooves, and 

 the posterior slope is ornamented with four or five radial 

 riblets. 



The hinge consists of a single thick, broad, triangular tooth 

 in the right valve, which fits in between two more slender 

 divergent teeth in the left. 



Margins coarsely crenulated. 



Dimensions. — Antero-posterior diameter, 3'75 ; umbo-ventral 

 diameter, 3*25 ; sectional diameter through both valves, 2 milli- 

 metres. 



Locality. — In shell sand at a depth of 22 fathoms, Encounter 

 Bay. 



Carditella subtrigona, spec. nov. Plate iv., fig. 10. 



Shell triangularly ovate, somewhat solid, inequilateral, 

 rather compressed, thick ; umbones prominent, inclined forward, 

 and considerably in advance of the centre. Surface ornamented 

 with fourteen radiating cost??, which are covered with closely 

 arranged, thick, compressed nodules ; the interspaces are deep, 

 a little narrower than the ribs, and are concentrically lirate. 



The front dorsal margin is slightly concave in front of the 

 umbo, thence rapidly sloping to the rounded anterior margin ; 

 the post-dorsal margin is ecurved, not so sloping, and longer 

 than the front dorsal margin. The posterior margin is roundly 

 truncated, and the ventral one regularly arched. 



The inner margin of the valves is strongly and squarely den- 

 tate. 



The left valve has two divergent cardinal teeth, the posterior 

 one of which is considerably longer than the other ; the right 

 ralve has a strong broadly triangular central tooth. There is 



