906 PELECYPODA. \_Eulamdlibmnchia. 



2. Venericardia difficilis, Deshayes, 1854. Plate 58, fig. 17. 



Cnrdita difficilis, Desh., P.Z.S., 1852 (1854), 103, pi. 17, f. 10, 17 ; M.N.Z.M., 

 159 ; Hutton, J. cle Conch., xxvi, 51 ; P.L.S. N.S.W., ix, 527. Veneri- 

 cardia difficilis, Desh., Index, 93. J T . itt/< nnidia, Hutton : von Ihering, 

 Anales Mus. Nac. Buenos Aires, xiv, 1907, 83, 282, 284, pi. 10, f. 68 ; 

 not of Hutton,. 



Shell ovato-transverse, inequilateral, swollen, radially ribbed, 

 light brown. Beaks oblique, contiguous, pointed, curved inwards. 

 Anterior end short, convex, dorsal margin concave ; posterior end 

 produced, subtruncated. the dorsal margin rather long, straight, very 

 slowly descending ; basal margin broadly convex. Luuulr small, 

 almost circular. Sculpture consisting of about 22 to 24 subangled, 

 crenato-scaly, sharp ribs, crossed by numerous concentric growth-lines, 

 the interstices subequal to the ribs. Epidermis thin, horny. Colour 

 yellowish or brownish, rarely with faint reddish spots near the umbones. 

 Interior porcellanous, pure - white. Margins crenate. Hinge - area 

 moderately broad, solid ; right valve with 3, left valve with 2 cardinal 

 teeth, all transversely finely striated. Ligament short, conspicuous, 

 external. Adductor-scars deeply impressed, subequal. Pallial line 

 simple, distinct. 



Length, 34 mm. ; height. 30 mm. ; diameter, 23 mm. 



Type in the British Museum (Cuming collection). 



Hob. Near Little Barrier Island, in 20 fathoms ; near Cuvier 

 Island, in 38 fathoms (Captain Bollons) ; near Channel Island, Hauraki 

 Gulf, in 25 fathoms ; Foveaux Strait, in 15 fathoms (A. Hamilton) : 

 Stewart Island, in 18 fathoms (Captain Bollons). 



Fossil.- Miocene and Pliocene. 



Subgen. 2. PLEUROMERIS, Conrad, 1867. 



Pleuromeris, Conrad, Amer. Journ. Conch., iii, 18K7. Type : Cardita Iri- 

 dentata, Say ; not of Reeve. 



Shell small, subtriangular, nearly equilateral, the hinge like 

 Venericardia, but the anterior and posterior right cardinals feeble, the 

 left valve with feeble anterior and posterior laterals. 



Miocene to Recent. 



3. Venericardia amabilis, Doshayes, 1854. Plate 63, fig. 7. 



Cardita amabilis, Desh., P.Z.S., 1852 (1854), 102, pi. 17, f. 8, 9 ; M.N.Z.M., 

 159 ; Webster, T.N.Z.I., xxxvii, 280. 



Shell small, suborbicular, laterally compressed, subequilateral, 

 radiately finely ribbed, yellowish-white spotted with reddish. Beaks 

 small, incurved, contiguous, sharply pointed. Anterior end a 

 little shorter, convex, the dorsal margin slightly concave ; posterior 

 end somewhat produced, broadly rounded ; basal margin convex. 

 Lunule small, ovate, flat, not deep. Sculpture consisting of 28 fine, 

 rounded, crenato-scaly radiate riblets, the interstices narrower than 

 the riblets. Colour yellowish-white, irregularly spotted with pale 

 brown or red. Interior white, pinkish in the umbonal cavities. Mar- 



