'ioni-phina.'] PELECYPODA. 993 



escutcheon not defined ; ligament very short. Margins of valves 

 smooth ; dorsal margin of both valves grooved on both sides of the 

 hinge-plate to receive the opposing edges. Pallial sinus small and 

 rounded. Hinge -plate short, broad from the umbo inwards, tri- 

 angular. Teeth : 3 cardinals in each valve ; rather long, straight, 

 separate, widely and equally divergent. In the right valve the median 

 is broad and triangular, generally solid, the posterior narrow and 

 feebly grooved. In the left valve the anterior is very long, the median 

 thick and feebly grooved, the posterior very thin. The left anterior 

 and the right median are sometimes feebly grooved. 



Distribution. Western Pacific, ranging from Australasia to Japan. 



1. Gomphina maorum, E. A. Smith, 1902. Plate 63, fig. 15. 

 Gomphina maorum, Smith, J. Mai., ix, 1902, 109, figs, in text. 



Shell small, equi valve, inequilateral, fairly solid, ovate-trigonal, 

 moderately convex, white with 2 fuscous radial rays and zigzag lines. 

 Beaks not very prominent, contiguous, post-median, incurved, very 

 slightly directed forwards. Anterior end longer, acutely rounded, 

 the dorsal margin long, a little curved, slowly descending ; posterior 

 end convex, the dorsal margin arcuate, descending ; ventral margin 

 broadly rounded. Lunule and escutcheon not defined. Sculpture 

 consisting of irregular strong concentric strise. Colour : 2 brown or 

 reddish radial rays, one down the middle of the valves, and the other 

 posterior to it ; the rest of the surface marked with irregular wavy 

 zigzag lines, always reddish towards the umbones. Interior white, 

 sometimes reddish, with faint radiate striae at the pallial line. Mar- 

 gins smooth, sharp. Hinge : Right valve with 3 diverging cardinals, 

 the median tooth strongest, triangular ; left valve with the same 

 number and arrangement of the cardinals, the median triangular 

 and lightly grooved ; dorsal margins grooved. Ligament short. 

 Adductor-scars subequal, the anterior ovate, the posterior roundish. 

 Pallial sinus small, broad, not deep, convex. 



Length, 16 mm. ; height, 13 mm. ; diameter, 8 mm. (type). 



Type in the British Museum. 



Hob. Cape Maria van Diemen (McGahey). 



Genus 3. PAPHIA, Bolten, 1798. 



Paphia, Bolten, Mus. Bolten., 1798, 175 ; not of Lamarck, 1799 and 1801, 

 or Fabricius, 1808, or Oken, 1815. Type : P. ala-papilionis, Bolten 

 (after Chemnitz). Tapes, Megerle von Miihlfeld, 1811. 



Animal with the borders of the mantle smooth ; siphons mode- 

 rately long, separated to some extent, papillate ; foot large, com- 

 pressed, pointed, grooved, and byssiferous ; palpi triangular, elongated ; 

 gills unequal. 



Shell elongate-oval, subcompressed, rather solid, with close con- 

 centric riblets ; lunule not constant, lanceolate ; inner margins 



8-2 Moll. N.Z. 



