105 



This species, whicli has the general form and shagreen - 

 sculpture of P. hifrons, differs from it chiefly by its compressed 

 truncated and more numerous ribs ; the valves are flatter and 

 the ears, particularly of the right valve, differ somewhat. 



Pecten palmipes, spec. nov. Plate v., fig. 4. Plate vii., figs. 4a — 46. 



Shell triangularly orbicular, inequilateral by projection of 

 posterior part ; slightly inequivalve, the right valve a little 

 more convex than the left ; ears large subequal, umbos de- 

 pressed. Right valve rayed with seven broad rounded plica- 

 tions, gradually becoming broader and flatter as they approach 

 the margin ; the interstitial spaces are narrow and deep. The 

 whole surface rayed with numerous linear ridges, the inter- 

 spaces minutely granulated. Posterior ear triangular, ob- 

 liquely truncated, rayed; anterior ear, larger, projecting, outer 

 margin curved, indented on the under side, radially ridged. Left 

 valve more depressed in the umbonal region, rayed with six 

 compressed elevated plicae, the flatly rounded surfaces of which 

 are bordered by two furrows, increasing in number towards 

 the front ; the interstitial spaces between the plicae are very 

 broad and deeply concave, bearing riblets in old shells towards 

 the margin. Spaces between the riblets minutely granulated. 

 Ears triangular obliquely or perpendicularly truncated, radially 

 Tidged, subequal, the anterior one larger. 



Dimensions of largest specimen. — Length 71, height 71, thick- 

 ness through both valves 27 millimetres. 



Localities. — Edithburgh, Torke Peninsula; oyster banks, 

 Aldinga Bay. 



This species has the general characters of the recent South 

 Australian P. hifrons, of Lamarck, possessing also its peculiar 

 granular shagreen-sculpture ; but it differs by the obliquity of 

 its valves, in being higher than long, and in the form of its 

 Tadial plicae ; the interior is plicated but not ribbed as in the 

 living species. 



Pecten Murrayanus, spec. nov. Plate vii., figs, oa—ob. 



Shell orbicular, fan-shaped, somewhat thin, scarcely equi- 

 lateral, projecting slightly in front, inequivalve ; valves rayed 

 with about 20 rounded ribs broader or equal in breadth to 

 the concave furrows, the whole crossed by close-set, thin, erect 

 lamellae coincident with the margin ; the lamellae increase in 

 deuseness from the umbo forw^ard. Interior with flat ribs 

 corresponding with the exterior furrows. 



Left valve slightly and regularly convex ; umbo acute, not 

 extended beyond hinge line. Ears unequal, the anterior large 

 roundly truncate, finely striated, perpendicularly and faintly 

 rayed ; the posterior elongate, arcuate, prominently rayed and 

 <joucentrically striated. 



