10 OCEAN LIFE. 



number of Polyps, though all appear to be very sensible to the 

 stimulus of light. Propagation is effected partly by eggs, partly 

 by germs or buds ; in many instances the last are not detached 

 from the parent stem, and thus there arise compound animals, 

 different individuals being connected. Our Polyps were, for the 

 most part, unknown to the ancients, and under this name entirely 

 unknown. By it they understood naked molluscs of the form of 

 the sepia, especially that genus which is now called Octopus by 

 Zoologists. From analogy, and from some resemblance of form, 

 Reaumer and Jussieu first gave the name, Polyp, to those fresh 

 water animals that had been described by Trembley, and which 

 were provided with a circlet of arms. 



To this class belong many marine animals, which, at first sight, 

 rather resemble plants than animals. Formerly, these so-called 

 sea plants were, on account of the hardness of the calcareous 

 substance of which they consist, referred to the mineral kingdom, 

 and corals were compared to branching crystallizations (Arbor 

 Dianse) and stalactites. 



The ancients believed that corals were soft whilst in the sea, 

 and only became hard in air. 



Even among later authors, traces may be found of the same 

 opinion, founded on defective observation, or on confusion of soft 

 species with hard ones. 



Up to the middle of the last century, it was the prevailing 

 view that these corals belonged to the vegetable kingdom. Mar- 

 sigli, in 1706, observed, on the shore of the Mediterranean, some 

 of these products, (Alcyonium, Corallium, Antipathes,) and found 

 in their pores little bodies that contracted when the stem was 

 removed from the water. Such bodies, or buds, he took to be 

 flowers, and so believed, that at length the view was definitely 

 established, which consigned these marine products to the vege- 

 table kingdom. But still, the animal odor which was observed, 

 opposed this view, as well as the chemical investigations of Geof- 

 froy, of Lemery, and of Marsigli himself, which demonstrated 

 ammoniacal constituents in the supposed sea-plants, just as in 

 animal substances. Peysonnel, a physician of Marseilles, in 

 1723, upon repeated examinations, found Marsigli's plants to be 

 animals. 



