LIVING MATTElt. 63 



within certain limits, the more simple the organism 

 the more beautiful is its shell or shield. 



Any description of these creatures is hardly 

 complete without some reference to their size. The 

 naked Amcela figured at the head of this paper 

 range from -g-oWth to rsoth of an inch in diameter, 

 and are of such extreme tenuity that they are not 

 in the least incommoded by being placed in a 

 compressorium that is, pressed between two thin 

 pieces of glass with a drop of water, in which they 

 move with perfect freedom. 



