POLYPS. 61 
name Polyp to those fresh-water animals that had been described 
by TREMBLEY, and which are 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 sub- 
stance of which they consist, referred to the mineral kingdom: and 
Corals were compared to branching crystallisations (Arbor Diane) 
and stalactites. Hence the name (Lithophyta, Lithodendra) stone- 
plants. The ancients believed that Corals were soft whilst in the 
sea, and only became hard in air: 
Nune quoque curaliis eadem natura remansit, 
Duritiem tacto capiant ut ab aere, quodque 
Vimen im cequore erat, fiat supra equora saxum. 
Ovip, Met. Iv. 750—752. 
Even amongst later authors traces may be found of the same 
opinion, founded on defective observation, or on confusion of soft 
species with similar hard ones. Up to the middle of the last cen- 
tury, it was the prevailing view that these Corals belonged to the 
vegetable kingdom. Marste@xt, in 1706, observed on the shore of 
the Mediterranean some of these products (Alcyoniwm, 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 
definitively established which consigned these marine products to 
the vegetable kingdom. But still the animal odour, that was ob- 
served, opposed this view, as well as the chemical investigations 
of Grorrroy, of Lemmry, and of Marsiaut himself, which demon- 
strated ammoniacal constituents in these supposed sea-plants, just 
as in animal substances. PrYSONNEL, a physician of Marseilles, 
observed at that place (1723) the Blood-Coral, and afterwards on 
the coast of Northern Africa examined different Madrepores and 
Millepores: the result was that he found Marstext’s Plants to be 
Animals, and named them Orties Corallines. He imparted his dis- 
covery to REaAumMuR: to whom the notion seemed so improbable, 
that in a short notice of it which he gave in the Mémoires of the 
Academy of Sciences at Paris 1727, he felt bound to suppress the 
discoverer’s name. Shortly afterwards, when PEYSONNEL’s dis- 
covery had been forgotten, TREMBLEY found in our country the 
fresh-water Polyp, and communicated his observations to REAUMUR. 
