APPENDIX. 355 



edges rather convex and somewhat sloping; anterior side bluntly 

 subangulated, bluish ash-coloured above ; posterior extremity rounded ; 

 beaks not inclined, often eroded ; luniile obsolete ; inside whitish, 

 stained with purplish liver-colour in front, anterior tooth slightly 

 crenulated, scarcely any pallial sinus. ^. . . 1 i. Malabar. 



Cytherea obliquata (t. 15, f. 24), Hani. Z. P. 1844, p. 109. — 

 Sow. Th. 2, t. 133, /. 125.— Dione o. Desk. Verier, p. 65. Ovate- 

 cordate (sometimes oblong-cordate), more or less tumid, rather strong, 

 nearly smooth, whitish, speckled with minute brown scattered linear 

 zigzags, which become denser upon the swollen umbones ; ligamental 

 edge rather convex, somewhat sloping; ventral edge subarcuated, 

 entire ; lunule large, indistinct, colourless ; beaks white, very slanting ; 

 ligament narrow; hinder extremity obtuse; inside white or pink. 

 If ... 2^-. Philippines. 



Cytherea rivularis (t. 15, f. 25, as C. scripta, var. !) — Venus r. 

 Bom, t. 5, /. 7, teste Desk. — Circe r. Soiv. Th. 2, p. 652, t. 139, 

 /. 46, 7, 8. — Desk. Vener. p. 84. Subquadrate, flat, solid, very in- 

 equilateral, glossy, white or yellowish white, with usually 2 or 3 im- 

 perfect chestnut rays, encircled with very narrow distant convex 

 folds that often (? usually) become obsolete in front and near the 

 arcuated and entire ventral margin, and are decussated by short 

 narrow curved diverging folds near the dorsal edges, of which the 

 front one is convex and moderately sloping, and the hinder one 

 straightish and much sloping ; umbones flattened ; beaks acute ; 

 slopes flat, chestnut-stained ; ligament sunken ; inside tinged with 

 rose-colour. 2. Australia. 



Cytherea Cyrilli (t. 15, £ 26). — Venus C. Scacchi, Lettera Test. 

 Kapolit. — C. apicalis, Phil. 1, p. 40, t. 4, /. 5. Small, rounded- 

 triangular, rather compressed ; glossy, speckled with pale chocolate 

 linear markings on a whitish ground, and usually adorned with a few 

 broken rays of the same hue ; closely and finely grooved throughout ; 

 ventral edge entire, subarcuated ; ligamental edge convex, not much 

 sloping ; hinder dorsal edge straightish or subretuse, much sloping ; 

 beaks acute, prominent, inclined ; lunule rather large, oblong-cor- 

 date, inconspicuous ; ligament sunken ; teeth and scars of section 

 Circe, -g-. Mediterranean. Evidently a variety of C. Minima. 



Cytherea affinis (t. 15, f. 27), Brod. Z. P. 1835, p. 45. — Sow. 

 Th. 2, p. 630, t. 132, /. 101. — Dione a. Desk. Vener. p. 73. 

 i" regard this shell as only a flattened variety of tortuosa, with 

 the concentric ridges sharper and more distant. 1 ... 1^. W. 

 Columbia. 



Cytherea albida (t. 15, f. 31). — List. t. 273, /. 109, quoted as 

 Venus a. by Gm. 3287.) — Chione a. Gray, Analyst. — C. Kingii, 

 var. Sow. Th. 2, t. 133, /. 131, probably. — Dione a. Desh. Vener. 



