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color, and about half an inch in length, protected by deep lami- 

 nated polygonal cells one-sixth of an inch wide; fig. 3, represents 

 the coral with the animal removed, its name astrea or star-like, 

 is derived from its radiated or starry appearance. Fig. 2, is a 

 magnified view of one of the polypes. The tentaculae, or arms, 

 are seen arranged around the mouth. The appearance of these 

 animals alive, and in activity, is most beautiful when viewed in 

 tranquil water. The surface of the rock appears like a living 

 mass, presenting a great diversity of appearance and color. The 

 Madrepore, or branched cellular coral, is well known, being per- 

 haps the most common species. It will be immediately recog- 

 nized upon inspecting the figure we have given below.. In some 



species after the fleshy investment perishes, the little cells appear 

 very numerous as in the figure. The white branched corals usu- 

 ally seen in collections belong to this genus. In the water, the 

 Madrepores are invested with fleshy integuments of vario.us colors 

 and each cell is furnished with its own polype. We have now 

 enumerated the several species of zoophytes most active in the 

 formations of reefs. The stony secretions of all these, when 

 bleached by the action of moisture and light, are of a dazzling 

 whiteness. There is however, a species of coral, Corattium ru- 

 krum, or red coral, the stony secretion of which is a bright red 

 color, very beautiful and susceptible of a high polish. A speci- 

 men of this coral is here figured. It consists of a brilliant red 

 stony axis invested with a fleshy or gelatinous substance of a pale 



