Oyster. They state that the crab, in order to obtain the 

 animal of the oyster without danger to their own claws. 

 watch their opportunity when the shell is open, to ad- 

 vance without noise and cast a pebble between their shells^ 

 to prevent their closing, and then extract the animal in 

 safety. " What craft !" exclaims the author " in animals 

 that arc destitute of reason and voice." We scarcely need 

 to add, that the craft existed only in the imagination of a 

 person who may have seen a crab feeding on an oyster 

 that had fortuitously closed on a pebblc. 



In the acceptation of Linne the genus Ostrea included 

 numerous species of various types of organization and ex- 

 terior character,although Lister had already circumscribed 

 the boundaries with correctness. From Linne's genus, 

 Bruguiere separated Pecten, Perna and Pedum, which 

 are provided with a byssus. Lamarck conducted the 

 analysis still further and formicd the genera Gryphara, Li- 

 ma and Malleus. Of these the two latter are attached 

 by a byssus. Lamark gives the following characters to 

 his family of Ostracea : " Ligament interior or half inte- 

 rior. Shell irregular, foliaceous, sometimes papyraceous." 

 It comprehends his genera Gryphaea, Ostrea, Vulsella, 

 Placunaand Anomia. The two latter have the ligament 

 interior, and Vulsella which is closely allied, is imbcded in 

 sponges, and has a cardinal callosity in each valve, extend- 

 ing somewhat into tae inter!(.r. Grypha^a is now by most 

 authors considered as a group of the present genus, distin- 

 guished from the others only by the curved umbo, an\I 1 

 may remark that I possess an individual of O. virginiea, 

 which has the incurved apex of Gryphaea. 



PI. 



