J.D. Dana on Zoophytes. 161 
The species are most abundant, however, in the waters of the 
temperate zone, and are common upon some portions of our own 
coast. 
Order <Actinoidea.—The <Actinoidea are marine zoophytes. 
All oceans have their species, yet in the torrid zone they more 
especially abound, and display most variedly their colors and sin- 
gular forms. 
The soft Actinide and the Alcyonaria have the widest range, 
occurring both among the coral reefs of the equatorial regions, 
and, to the north and south, beyond the temperate zone. The 
Mediterranean affords species of Gorgonia, Corallium, and Alcy- 
onium, besides numerous Actinie. The coasts of Britain have 
also their Alcyonia and Actinias, and from far in the northern 
seas, come the Umbellularia, and some other species of the Pen- 
natula family. 
Among the coral-making Actinaria, the Madrepore and Astrea 
tribes are almost exclusively confined to the coral-reef seas,—a 
region included mostly between the parallels of 28° north and 
south of the equator,—while the Caryophyllia family are spread 
as widely as the species of Actinia. Several species of Caryo- 
phyllidee occur in the Mediterranean, and others in the high north- 
ern seas, and they are met with at depths of several hundred feet. 
They are also common among the coral-reefs of the tropics.. - 
‘The Madreporacea and Astraeacea, with the Gemmiporide, are 
the principal constituents of coral reefs. ‘The temperature limit- 
ter temperature of the ocean on the outskirts of the reef-growing 
be a temperature which they can endure, and not that in 
which they germinate. The extremes which they will survive 
prove only their powers of endurance, and do not affect the 
above statement; for their geographical distribution will be de- 
termined by the temperature which limits their powers of ger- 
The temperature of the ocean in the warmest parts of the Pacific, 
varies from 80° to 85°, and here Astreas, Meandrinas, Madrepores, 
&c., are developed with peculiar luxuriance, along with thousands 
of other strange and beautiful forms of tropical life. A range 
Pocillopore: prevail, and there are very few species of the genera 
Astrea, Mussa,* and Meandrina, which are common nearer the 
equator, 
Oe aig 4 lia of Blainville, Mussa of Oken. 
Srconp Series, Vol. I on 8.—March, 1847. 21 
