INTRODUCTION. 
11 
The following are the Worms of the Order Mol- 
LuscA, which construct and inhabit calcareous 
shells, the objects of our present consideration. 
Doris, or (according to Poli) Lophyrus ; Chiton. 
Triton ; Lepas. 
Ascidia; Pholas, My a, Solen, Mytilus. 
Tethys ; Tellina, Cardium, Mactra, Donax, 
Venus, Spondylus, Chama, Area, Ostrea. 
Liniax ; Pinna, Conus, Cypraa, Bulla, Voluta, 
Buccinum, Strombus, Muj^ex, Trochus, 
Turbo, Helix, Nerita, Haliotis, Patella. 
Terebella ; Hentalium, 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 
