ijo C O N C H O L O G Y. 



from chamber to chamber, Is filled with 

 ail appendage or tail of the animal*, like a 

 gut or firing f- 



Mr. Hookc (Philofophical Experiments 

 and Obfervations, p. 306.) imagines the ani- 

 mal ufes this tail or gut, which fills the 

 pipe or fiphunculus at will, as its necef- 

 fities require, to exhauft the water or air 

 from the chambers, or vice verjh, to fill 

 them with either; by which aclions he 



* See the Gentleman'* Magazine many years ago on 

 this fubjecl. The fiphunculus is a dilatable tube under 

 the command of the animal. When it is dilated, 

 like the fwimming-bladder of a fi(h, it renders the 

 the Nautilus buoyant. When it is contracled, the fifh 

 and {hell fink, and juft to fuch a degree as the prefent 

 occafions of the animal require. I believe no water 

 ever enters this tube. 



t I have my doubts whether the Nautilus fifh in- 

 habits more than one chamber of his Shell. I think, 

 it does not ; for if it does, how is the fifh ever got 

 from thofe chambers, as the fiphunculus is fo fmall ? 



renders 



