CHAM A CLAM OR CLAMP. 175 



the Chamse ; one exhibited at Sir Joseph Banks', 

 was valued at between two and three hundred 

 pounds. The colour of Chama Gigas, is a dingy 

 white : the hinge is furnished with a cartilage of 

 a dull colour, which when cut and polished, is as 

 beautifully iridescent as Opal. 



CHAMA Cor* 



HEART CLAM. 



Specific Character. Shell equivalve, globose, 

 heart-shaped when viewed from the posterior 

 side ; thick, strong, smooth, or only slightly 

 striated transversely : umbones large and promi- 

 nent, apices involute, and turned to one side : 

 colour pale yellowish brown, covered with a dark- 

 er epidermis, decorticated at the umbones. Shell 

 about three inches long, and two and three quar- 

 ters broad. 



This shell has but very rarely been found in 

 the British seas ; it is much prized on account 

 of the singular and graceful beauty of its form. 



It belongs to the new genus Isocardia. 



CHAMA Hippopus.^ 



BEAR'S PAW CLAM. 



Specific Character. Shell equivalve, inequi- 

 lateral, thick, heavy, longitudinally ribbed 



* Plate IX. figure 3. f Plate IX. figure 2. 



