138 UNIVALVES. 



OBSERVATIONS ON THE SHELL AND ITS 

 INHABITANT. 



The animal inhabiting these elegant shells is 

 soft and fleshy, having a large portion of its body 

 enveloped in the mantle ; its head is furnished 

 with two eyes, and round its mouth are arranged 

 like rays eight elongated and pointed tentacula 

 or arms. Two of these have a thin membrane 

 extending more than half their length. This 

 singular appendage the animal can expand or 

 draw in at pleasure. The shell is of a thin 

 paperlike substance, resembling in form a kind 

 of boat. Few objects can be conceived more 

 interesting than this beautiful animal seated in 

 its pearly little vessel ; two tentacula erected, 

 with their membrane unfurled like a sail, whilst 

 the remaining six, suspended over the sides 

 of the little bark, perform the office of oars. 

 When wafted by propitious gales, it calmly rides 

 over the waves ; but should a storm threaten, or 

 an enemy approach, it precipitately hauls in its 

 tackle, shrinks into its shell, and drawing in 

 water to add to its weight, seeks protection in the 

 depths of the sea : the danger over, it diminishes 

 the gravity of its shell by ejecting the water, and 

 rises again to the surface. 



It has long been a doubt whether this animal 

 is the true inhabitant of the Argonauta, and it is 

 supposed by many naturalists to be one of the 

 eight-armed Sepia or Cuttle-fish, which, like the 



