84 



CUTTLE-BONE. 



muscular piston, exactly fitting the cavity. No-vf, 

 if the circumference of the sucker be closely 

 pressed against any substance of sufficient size 

 and consistency, and the piston withdrawn, a 

 vacuum is at once created, and powerful adhesion 

 takes piace. As, on an average, each cuttle is 

 furnished with nine hundred suckers, the force of 

 its hold may be imagined. 



There is a substance that is often to be picked 

 up on the shore, and oftener to be purchased at 

 the perfumer's shops, known by the name of 

 cuttle-bone, and when reduced to powder, used 

 for various purposes. This so-called cuttle-bone 

 is not bone at all, but a very wonderful structure, 

 consisting almost entirely of pure chalk, and 

 having been at one time embedded loosely in the 

 substance of some departed individual of the 

 species called Sepia officinalis. The "bone" is 

 enclosed within a membranous sac within the 

 body of the cuttle, by which sac it is secreted, 

 and with which it has no other connexion, drop- 

 ping out when the animal is opened. On taking 

 one of these objects into the hand, its extreme 

 lightness is very evident, and if it be cut across 

 and examined through a lens, the cause of the 

 lightness will be perceived. The plate is not 

 solid, but is formed of a succession of excessively 



