INTRODUCTION. 11 



The following are the Worms of the Order Mol- 

 lusc a, which construct and inhabit calcareous 

 shells, the objects of our present consideration. 



Doris, or (according to Poli) Lophyrus; Chiton. 



Triton; Lepas. 



Ascidia ; Pholas, Mya, Solen, Mytilus. 



Tethys; Tellina, Cardium, Mactra, Donax, 

 Venus, Spondylus, Chama, Area, Ostrea. 



Limax; Pinna, Conus, Cyprcea, Bulla, Voluta, 

 Buccinum, S trombus, Murex, Trochus, 

 Turbo, Helix, Nerita, Haliotis, Patella. 



Terebella ; Dentalium, Serpula, Teredo. 



Nereis; Sabella. 



The animals inhabiting the Anomia and Nau- 

 tilus are either sui generis, or have hitherto been 

 unsatisfactorily described. 



It has been generally supposed that the Mollus- 

 cous animal, of the genus Sepia, mentioned by seve- 

 ral naturalists and delineated by some of them, as 

 the inhabitant of Argonauta, was also the original 

 fabricator of the Shell. This fact has, however, been 



