174 BIVALVES. 



suggested the name of Noah's Ark, and from 

 this fancied resemblance in one species to the 

 ark, the genus owes its designation. 

 { Inhabits the Mediterranean, Indian Ocean, 

 West Indies, and Britain. 



ARCA Undata. 

 LETTERED ARK. 



Specific character. Shell suborbicular, nearly 

 smooth, with faint reticulated")" striae ; margin 

 crenated ; teeth in a curved line ; colour white, 

 variegated with yellowish red spots, in undulated 

 transverse bands. 



Inhabits the West Indies, and shores of Italy. 



GENUS. OSTREA.J 



OYSTER, SCALLOP, OR PECTEN. 



Generic character. Shell bivalve, generally 

 inequivalve, inequilateral, more or less eared; 

 hinge without teeth, but furnished with an ovate 

 sinus, in which is fixed an elastic cartilage ; it 

 has generally lateral transverse grooves. 



* Plate IX. figure 5. 



f Reticulated, having the appearance of net work, from the 

 Latin reticulum, a small net. 

 J Plate IX. figures 7, 8. 



