72 CLASS II. 
nearly one-half of the numerous species is found in America. Of 
swimming polyparies (Pennatule), many species are found in the 
Mediterranean, the Indian Ocean and the North Sea, and the large 
Umbellaria of Greenland, which attains a length of six feet, is 
remarkable. Of the stony polyparies, the greater number occur in 
the seas of hot countries, as ex. gr. Madrepora, especially Astrea, 
Caryophylla, Fungia, Meandrina. Most of the species of the last 
genus are found in the Indian Ocean and South Pacific. The Red 
Sea also has very many species from the division of these stony 
polyparies. More than one-fourth of the known species of this 
class were found there by EurenberG. Notwithstanding the 
proximity, it seems that the Red Sea, with the exception of some 
species of Actinia, has no species in common with the Mediterranean. 
Tsis nobilis (Corallium rubrum) appears to occur in the Mediter- 
ranean alone. 
Of many genera numerous fossil species are found, especially of 
those whose species now live in hot regions. Thus the genus 
Astrva numbers more fossil than living species: and these petrified 
remains belong principally to the Jura- and chalk-formations. Still 
more numerous are the fossil species, as compared with those now 
living, in the genus Turbinolia. A genus which appears to connect 
Fungia and Turbinolia, Cyathophyllum of GoLpFuss, has quite died 
out, and occurs in transition limestone. In the same way fossil 
species alone are found of the genera Certopora, Favositis, Pustu- 
lopora, Heteropora, Catinipora and Aulopora. The fossil Polyparies 
prove, like all other remains of an earlier vegetable and animal 
world, that the surface of our earth had in earlier times a higher 
mean temperature than it has now. 
