98 CONCHIFERA, DIMYAIRA, 



This is one of the most common species on the coast near Edinburgh. At Mus- 

 selburgh they are often thrown ashore in immense numbers. 



V. virginea, Gmel. Shell subovate, with numerous smooth, flat, 

 concentric ridges, and narrow intervening furrows ; anterior de- 

 pression lanceolate ; colour white, with various markings of a 

 brownish red colour, 1^ inch long by 2 broad. Inhabits Euro- 

 pean coasts. B. Brown's Illust. pi. 20, fig. 6, 7^ 8, 9. 



V. ovata, Penn. Shell ovate, trigonal, slightly compressed, with 

 longitudinal grooves and transverse striae ; posterior depression 

 oblong, and elevated in the middle ; margin crenulated ; colour 

 dirty white. Coasts of Britain. B Pen. Brit. Zool.iv. pi. 59, fig. 3. 

 Fossil species of this genus are found on the continent, and in Britain in oolite, 



gray chalk marl, crag, green sand, and London clay. Fleming; Brit. An. 449. 



Gen. 21. CYTHEREA, Lam. Venus, Lin. 

 Shell equivalve, inequilateral, suborbicular, trigonal or trans- 

 verse ; four primary teeth in the right valve, of which three 

 are divergent, and approximated at their base, and one iso- 

 lated ; three primary diverging teeth in the other valve, and 

 a hollow ; no lateral teeth. 



All the shells of this genus are marine, and some are found fossil. 

 * Anterior primary tooth with a striated canal, or the margin den- 



tated. 



C. lusoria, Lam. Shell somewhat heart-shaped, ponderous, smooth, 

 white, with two chestnut interrupted zones. 2^ inches long. In- 

 habits seas of Japan and China Chem. pi. 32, fig. 340. 

 The Chinese and Japanese use this shell, the inside painted with figures, in cer- 

 tain games. 



C. meretrix, Lam. Shell triangular, heart-shaped, shining, compres- 

 sed at the posterior end ; cartilage slope rather protruded, and 

 the posterior depression obsolete ; colour white, pale greenish, or 

 yellowish brown, marked with darker spots or lines. 1 J inch long. 

 Inhabits Indian seas. D'Argenv. pi. 21, fig. F. 



** Anterior primary tooth not striated in its canal, nor dentated on 



the margin. 



C. erycina, Lam. Shell ovate, golden-brown, variegated and rayed 

 with purple ; transverse ribs broad and obtuse ; posterior depres- 

 sion ovate. 2^ inches long. Inhabits European and Indian seas. 

 Chem. vi. pi. 32, fig. 337. 



C. Chione, Lam. Shell somewhat heart-shaped, glossy, with the pos- 

 terior depression oblong and acute ; pale chestnut coloured, with 

 darker longitudinal rays ; margin entire. 2| inches long. In- 

 habits European seas. B Penn. Brit. Zool. iv. pi. 54, fig. 2. 



C. castrensis, Lam. Shell roundish heart-shaped, ventricose, white, 

 with transverse angular chestnut or purple angular lines, fimbri- 

 ated on one side ; posterior depression heart-shaped, with a sur- 

 rounding groove. 1 A inch long. Inhabits Indian Ocean. Lister) 

 pi. 162, fig. 98. 



