Area.] PELEt'YPODA. 849 



the area bare (Acar], or leaving a bare space before and behind it 

 (Fossularca). 



1. Area reticulata, Gmelin, 1790. Plate 58, fig. 3. 



Area reticulata, Gmel., Syst, Nat., <<!. 13, 1790, 3311; Dall, "Blake" 

 Pelecypoda, 1886, 242; Dall and Simpson, Moll, of Porto Rico, 1901. 

 4(50. A. squamosa, Lamarck, A.s.V., vi, 1819, 45. A. dontingensis, 

 Lamarck, ibid., 40; Chall. Rep., xiii, 265. A. clathrata, Lamarck, ibid., 

 46 (fide Deshayes). A. gradata, Broclerip and Sowerby, Zool. Journ.,iv, 

 1829, 365. Byssoarca divaricata, .Sowerby, P.Z.S., 1833, 18 ; Conch. 

 Icon., ii, 1844, pi. 16, f. 108. ? Area donaciformis, Reeve, Conch. Icon., ii, 

 1844, pi. 16, f. 104 ; C'rit, List, 48 ; Mutton, P.L.S. N.S.W., ix, 528. 

 Barbatia pusilla, Sowerby, C.M.M., 79 ; J. de Conch., 1878, 79 ; M.N.Z.M., 

 162 ; not of Sowerby. B. rcticulata, Chemnitz, Index, 94. 



Shell ovato-subrhomboidal, inflated, rather small, reticulated, 

 equivalve, inequilateral, anterior and posterior slope carinated, liga- 

 mental lozenge extending very little behind the beaks, yellowish- 

 white or light brown. Beaks situate at about the anterior third, 

 distant, pointed, and directed forwards. Anterior end short, rounded ; 

 posterior end larger, the dorsal margin angled behind, the posterior 

 margin obliquely descending and very narrowly rounded or angled 

 on meeting the straight basal margin. Cardinal area deeply excavated, 

 narrowly elliptical. Sculpture consisting of close fine radial riblets 

 with deep furrows between them, crossed by equally prominent con- 

 centric riblets, cancellating the surface ; cardinal area finely longi- 

 tudinally striated. Colour light brown, sometimes yellowish-white. 

 Interior whitish, dull, with faint radiate strife. Margins crenate, 

 but the foramen for the byssus smooth. Hinge-plate narrow in the 

 middle, widening at both ends, slightly curved ; teeth small and vertical 

 beneath and some distance behind the beaks, oblique and slightly 

 curved at the ends of the plate. Ligament small, cordiform, between 

 the umbones and very slightly extending posteriorly, leaving the area 

 free in front and behind. Adductor-scars unequal, the posterior scar 

 somewhat larger. Pallial line simple. 



Length, 23 mm. ; height, 13 mm. ; diameter, 11 mm. (large speci- 

 men). Length, 12 mm. ; height, 8 mm. ; diameter, 7 mm. (usual size). 



Hab. Throughout New Zealand ; rare, according to Hutton : 

 Stewart Island, in 15 fathoms (A. Hamilton). Also Australia and 

 Tasmania, Japan, Antilles, Gulf of Mexico, Brazil, Mozambique, Cape 

 Verde Islands, &c. 



It has not been found living from more than 100 fathoms. (Dall.) 



Subgen. 2. SCAPHARCA (Gray), Dall, 1898. 



Scapharca, Gray, P.Z.S., 1847, 206 ; Dall, Trans. Wagner Free Inst,, iii, 

 pt. iv, 1898, 617. Type : Area inequivalvis, Brug. 



Shell inequivalve, the left valve larger than the right, oval or 

 oblong, sub quadrangular, subequilateral, ventral margins closed, sur- 

 face with radial costse, teeth more or less oblique. Animal with a 

 byssus. 



