Lima.] PELECYPODA. 883 



KEY TO SUBGENERA. 



A. Valves gaping, inequilateral . . . . . . . . LIMA, s. str. 



B. Valves closed, equilateral . . . . . . LIMATULA. 



Subgen. 1. LIMA, s. str. 

 Hinge edentulous; valves usually gaping, inequilateral. 



Sect. 1. LIMA. s. str. 

 Sculpture radial, submargins impressed. Type : L. lima, L. 



KEY TO SPECIES. 



A. Shell attaining a moderately large size, solid, ribs stout, valves 



gaping . . . . . . . . . . . . lima. 



B. Shell small, thin, riblets numerous and very fine, valves closed sydneyensis. 



1. Lima lima, Linne, 1758. Plate 58, fig. 11. 



Ostrea lima, Linne, Syst. Nat., ed. 10, 1758, 699. Lim.ct lini'i, L. : Lamarck, 

 Mem. Soc. H.N., Paris, 1799, 88. L. squamosa, Lamarck, A.s.V., vi, 

 1819, 156 ; Thes. Conch., i, 84, pi. 21, f. 1, 18 ; Hanley, Cat. Rec. Biv. 

 Shells, 266; Conch. Icon., xviii, 1872, pi. 2, f. 10; C.M.M., 83; 

 Hutton, J. de Conch., xxvi, 55 ; Chall. Rep., xiii, 287. L. zealandica, 

 Sowerby, P.Z.S., 1876, 754, pi. 75, f. 1 ; M.N.Z.M., 172 ; Hutton, P.L.S. 

 X.S.W., ix, 531. 



Shell solid, inequilateral, rather inflated, radiately ribbed, slightly 

 gaping on each side. Beaks elevated, distant, incurved, sharply 

 pointed, the small prodissoconch smooth. Anterior end obliquely pro- 

 duced, straight ; 'posterior end obliquely rounded, with small oblique 

 triangular ears ; basal margin regularly convex, forming an obtuse 

 angle with the anterior margin. Submargin large, oblong, concave, 

 with radiate riblets and concentric striae. Sculpture : Ears with a few 

 concentric ridges produced above into triangular scales ; discs with 

 18 strong radiating ribs, which are covered with large rough elevated 

 scales. Colour whitish, the ribs sometimes reddish-brown. Interior 

 white, polished, the ribs distinctly visible. Margins strongly dentate. 

 Hinge-line moderately broad, smooth,' with a tubercle on each end. 

 Resilium triangular, central, with a triangular area reaching to the 

 beak above it on each side ; in front and behind a narrow triangular 

 ligament, which is wholly external. Adductor - scar large, double, 

 slightly posterior. Pallial line simple. 



Diameter Ant. -post., 42 mm. ; dorso-ventral, 49 mm. : thickness, 

 28 mm. 



Type of L. squamosa, Lam., in the Mus. Hist. Nat., Geneva ; of 

 L. zealandica, Sow., in the British Museum. 



Hob.- Dusky Sound, in 30 fathoms ; Preservation Inlet ; Stewart 

 Island ; Foveaux Strait ; near the Snares, in 50 fathoms (Captain 

 Bollons) ; south of Oamaru, in 40 fathoms (E. R. Waite). 



