PLATE LVIII. 



The Mactra lutraria is so very similar in general appearance to the 

 My a Arenaria, that without attending to the foliated hinge of the 

 latter, they may be confounded with each other. Both shells are 

 scarce on the British coasts, except in certain situations. Da Costa 

 says the Mactra lutraria is found in plenty at Scarborough, in Nor- 

 thumberland, Lancashire, <kc. and on the shores of Scotland. Dr. 

 Maton found them on the coast of Cornwall ; and we met with 

 them very fine, perfect, and beautifully coloured, on the sands near 

 Laugharn, South Wales. 



The general colour is yellowish, tinged with orange, and irregu- 

 larly clouded with brown ; and often glossed with a delicate white ; 

 the epidermis brown. 



