FOSSIL REMAINS OF POLYPES. 333 



SECTION II. 



FOSSIL REMAINS OF POLYPES. 



It was stated in our Chapter on Strata of the Transition 

 Series, that some of their most abundant animal remains 

 are fossil Corals or Polyparies. These were derived from 

 an order of animals long considered to be allied to marine 

 plants, and designated by the name of Zoophytes ; they are 

 usually fixed, like plants, to all parts of the bottom of the 

 sea in warm climates which are not too deep to be below 

 the influence of solar heat and hght, and in many species, 

 send forth branches, assuming in some degree the form and 

 aspect of vegetables. These coralline bodies are the pro- 

 duction of Polypes, nearly aUied to the common Actinia, or 

 Sea Anemone of our own shores. See PI. 54. Fig. 4. Some 

 of them, e. g. the CaryophyUia, see PI. 54. Figs. 9, 10. are 

 solitary, each forming its own independent stem and sup- 

 port; others are gregarious, or confluent; living together 

 on the same common base or Polypary, which is covered 

 by a thin gelatinous substance, on the surface of which are 

 scattered tcntacula, corresponding with the stars on the 

 surface of the coral, (see PL 54. Fig. 5.) 



Le Sueur, who observed them in the West Indies, 

 describes these Polypes, when expanded in calm weather at 

 the bottom of the sea, as covering their stony receptacles 

 with a continuous sheet of most brilliant colours. 



The gelatinous bodies of these Polypes are furnished with 

 the power of secreting carbonate of Lime, with which they 

 form a basis of attachment, and cell of retreat. These cal- 

 careous cells not only endure beyond the life of the Polypes 

 that secreted them, but approach so nearly to Limestone 

 in their chemical composition, that at the death of the 



