ZOANTHARIA. 155 



The polypidom is in the form of a fan, with many very unequal 

 branches; the larger branches are smooth, the middle-sized are 

 covered with small points. This fine zoophyte is found in the seas 

 which surround the Isle of Bourbon and the Mauritius, a fine example 

 of which is to be seen in the collection of the Museum of Natural 

 History of Paris. 



ASTR^ACEA. 



How diversified are the forms of aquatic life ! " Nature revels in 

 these diversities," to paraphrase the saying of one of the ancient kings 

 of France. Here are animals, the frame of which might have been 



- 



Fig. 70. Abtrea punctifera (Lamarck). 



designed by a geometrician. They are called Star Corals (Astrea). 

 Their resemblance to the well-known figure was too striking to escape 

 the observation of naturalists ; but the organization of these creatures 

 of the ocean is far from being rigorously regular, for Nature rarely 

 employs perfectly straight lines, giving an evident preference to 

 circles and waving lines. 



The Astrea are inhabitants of the Indian Ocean, where they are 

 found in a great variety of forms, which has led to their subdivision 

 into many genera by Messrs. Milne Edwards and J. Haime. The 

 animals are short, more or less cylindrical, with rounded mouth placed 

 in the centre of a disk, covered with a few rather short tentacula ; the 

 cells are shallow, with radiating lamellae in Astrea punctifera (Fig. 70), 

 forming by their union a many-formed coral, which often encrusts 



