LECTURE XL 
159 
ent from the rest, and exactly similar in all re- 
spects to the genus Sepia or Cuttle, except in 
having expansile membranes at the two foremost 
arms, a suspicion hcis often been entertained, that 
it could not be the true or proper inhabitant of 
the shell, but that it was some species of Cuttle, 
which was a usurper of the shell in which it swam ; 
and this suspicion was strengthened by the con- 
sideration that many of the Univalve shells are 
occasionally inhabited or usurped by some of the 
smaller species of the Crab-tribe, as the Cancer 
Bernardus, Diogenes, and others. 
As the animal of the Paper-Nautilus is ex- 
tremely quick-sighted, and descends from the sur- 
face on the least appearance of danger, it is very 
difficultly obtained, and is principally found after 
a storm, during which it is sometimes driven 
ashore. 
Most of the European naturalists seem, till 
lately, to have coincided in opinion that the ani- 
mal was not the real and proper inhabitant of 
the shell, notwithstanding the testimony of the 
celebrated Dutch observer, Rumphius, who, above 
a century ago, during his residence in the island 
of Amboyna, had opportunities of examining the 
