INTRODUCTION. 1 1 



The following are the Worms of the Order Mol- 

 LIJSCA, which construct and inhabit calcareous 

 shells, the objects of our present consideration. 



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



Triton ; Lepas. 



Ascidiaj Pholas, Mt/a, Solen, Mytilus, 



Tethys j Tellina, Cardium, Maclra, Donax, 

 VenuSj Spondylus, Chama, Area, Ostrea, 



Limax j Pinnae Conus, Cyprcea, Bulla, Fbltita, 

 Bicccimim, Stromlus, Murex, Trochus, 

 Turlo, Helix, Nerita, Haliotis^ Patella, 



Terebella; Dentalium, Serpula, Teredo, 



Nereis; Salella. 



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 



