I9I7.] 



J. HORNELU : Indian species of Meretrix. 



155 



Valves trigono- 

 sub-orbicular. 



Species. Characteristics. 



Valves with or without obscure and 



discontinuous broad rays ; vulva 



obscure, margin indefinite. 

 Valves without rays ; vulva dark, 



very conspicuous, with clean-cut 



margin. 

 Colour uniform chestnut... 



Mereti'i.x 

 nieret'-ix 

 (Linn. ) 



Sections. 



ype. 



B. Anterior cardinal 

 50 mm. 



. Var. /;»- 

 pudtca 

 (C.'hemnitzj. 

 _, Var, casta- 

 nea (Lam- 

 arck 1. 

 Valves rayed with iniiiiefons con-"^ 4. Var. auru- 

 tinuous bands of dark colour, some > ra, var. nov. 

 broad, others narrow. j 



Valves rayed with fivo wide brown ) 5. Var. moi'- 

 bands, often incomplete. ) phina{L,Rm- 



arck). 

 Valves concentrically zoned either ~) 6. Var. zona- 

 with solid or with zig-zag chevron- > ria (Lam- 

 shaped dark bands. ) arck). 



tooth in left \'alve entire ; length of shell usually less than 



\ 



Valves usual- 

 ly trigono-cord- 

 ate ; sometimes 

 ovate to oblone. 



M. casta J 

 /(Chem.) 



Shells large and ventricose, cordate ; ~\ 

 without colour bands, except rarely ^ i. 

 upon the umbones. -> 



Shell ovate to oblong with or without ^ 

 two obscure and often imperfect ra- 

 dial bands ; hinges elongate ; um- 

 bones nearly medium, curved 

 straight inwards, usually eroded. 



Shell corbiculiform ; extremely thick ; 

 hinge short ; teeth very stout. Sub- 

 fossil only. 



Type. 



I 2. Var. 

 \-ovutn 



J 



(Hanley). 



3. Var. sat- 



para'eiisis 



(Preston). 



IL Pallial sinus deep, almost seiui-circiilar, ivitli a ventral lion/ ending in an 



acute point. 

 ' Shell concentrically zoned with 7 ^ jypj. 

 chevron-shaped markings. 5 ' • 



Shell unicoloured, except occasionally ") 2. Var. fla- 

 on the umbones. ) "vci, var. nov. 



Valves 

 cuneate. 



sub- 



M. atten- 

 ■ uata, 

 Dunker. 



I758> 

 1782. 



1835- 



1835- 



1864. 

 1869. 



1915- 

 1916. 

 1916. 



1. Meretrix meretrix (Linn,). 



Venus meretrix, Linn., Syst. Nat., loth ed., p. 686. 



,, ,, seu impudica, Chemnitz, Conch. Cab., Vol. VL pi 33. 



Cytherea meretrix, Lamarck, Atiim. sajis. Vert., 2nd ed., Vol. VL 

 p. 300. 

 ,, impudica, Lamarck, ibid., p. 299. 



,, castanea, Lamarck, ibid., p. 299. 



,, zonaria, Lamarck, ibid., p. 299, 



') graphica, Lamarck, ibid., p. 300. 

 ,, morphina, Lamarck, ibid., p. 300. 



,, graphica, castanea, zonaria, impudica, and inorpliina, 

 Reeve, Condi. Icon., XIV. Cytherea, figs, i, 6, 9, 10 and 

 12. 

 meretrix, Romer, Monographic der Molluskengattung 

 Venus, Linne, Band L Sub-genus Cytherea, p. 27, pi. 

 viii, all figs. 

 casta, Preston (in part), Rec. Ind. Mus., Vol. XL p. 300. 

 ovum, Preston, ibid., p. 300. 

 meretrix, Annandale and Kemp, Mem. Ind. Mas. Vol. V, 



P-35I- 

 ovum, Annandale and Kemp, ibid., p. 352, 



Meretrix 



