78 GENUS XIV. OSTREA. 



ternal, fixed in a long narrow groove, the lower valve 



hollowed (see Ostrea spondyloides, Chemn. vol. 8. t. 72. 



f. 669, 670). 



Between Perna and Pecten will very properly come in a 



new genus formed by Lamarck for a shell lately brought from 



the Red Sea, which he calls Crenatida. Shell flat, irregular ; 



hinge linear, crenulated, with a row of small roundish hollows 



which receives the cartilage ; no byssus (see Crenatida my- 



tUoides, f. 44). 



m 





