In consequence of an omission the reader is requested to cancel 

 the account of Cythercea from C. Chione to C. Reflexa and 

 substitute the following. 



" C. CHIONE. Venus C. Tnrt. Lin. Mont. Test. Brit., vol. 1, p. 115. 

 Flem. Brit. An., p. 14-1. Queens. Common in sandy bays, sometimes 

 in considerable numbers. The beauty of the shell varies with the 

 ground. It is not unfreqnently found with a black margin, and I 

 have obtained it wholly black. 



* C. EXOLETA. Venus E. Turt. Lin. Pen. Brit. Zo., vol. 4, pi. 54, 

 fig. 49. Mont. Test. Brit., vol. 1, p. 116. C. E. Flem. Brit. An., 

 p. 445. Common. 



*C. LINCTA. Venus Exoleta. Pen. Brit. Zo., vol. 4, pi. 56, fig. 49. 

 Mont. Test. Brit., vol. 1, p. 117, where he supposes this to be the 

 young of the last species ; but in which opinion the judgment of 

 Naturalists has decided against him. In recent shells of equal size, 

 the distinction seems clear. C. L. Flem. Brit, An., p. 445. Not 

 common on the shores; but single valves adhere to the Byssus of 

 the Pinna, from the depth of 50 or 60 fathoms. 



• C. OVATA. Venus O. Pen. Brit. Zo., vol. 4, pi. 5G, fig. 56. 

 .Mont. Test. Brit., vol. 1, p. 120. C. O. Flem. Brit. An., p. 444. 

 Common, chiefly from deep water, attached to the Byssus of the 

 Pinti a. 



C. TIGERINA. Venus T. Turt. Lin. Mont. Test. Brit., vol. 1, 

 p. 119, pi. 4, fig. 1. C.T. Flem. Brit. An., p. 445. Rare. 







