COLLECTION OF POLYPI. 53l 



by which they are protected, as the mollusca by 

 their shells. As these tubes, which by their assem- 

 blage compose what is generally called a polypus, 

 have been moulded upon the animal itself, they 

 give us an idea of its form ; but this notion being 

 too imperfect for naturalists, M. Savigny lately 

 undertook to examine several species of this 

 order, and discovered in their organization the 

 most curious and extraordinary phenomena. 



A very remarkable circumstance amongst the 

 numberless animals which unite to construct a 

 polypus, is the regularity and order w r ith which 

 they work and branch their cells, so as to 

 obtain for the whole set a general form or 

 outline, which, differing in the various species, 

 is uniform in each. Some are wrought into 

 rounded masses, others into blades or leaves, the 

 shape of a cup, or that of a shrub. Nothing 

 can be more curious than to observe, at low 

 \vater. on the shores of the tropical islands, the 

 polypi so diversified in their form and colour, 

 with their surface in perpetual motion from the 

 activity of the small animals half protruded from 

 their cells. 



The polypi act a very important part in the 

 creation from the prodigious facility with which 

 they multiply. To them is due the existence, ex- 

 tent, and rapid increase of those shoals which 



34. 



