ALCYONARIAN POLYPS. 85 
many forms of tabule, are certainly characters not opposed 
to the alliance of these corals with the Alcyonarians,’’? and 
gives other reasons of importance in favor of this view. 
The group of Antipathea, represented by Antipathes ar- 
borea Dana, of the Feejee Islands, produce compound 
groups by budding, growing in the form of delicate shrubs. 
The polyps have usually six tentacles, though in Gerardia 
they have twenty-four. 
Order 2. Alcyonaria.—To this group of polyps, which 
have eight serrated or feathered tentacles, belong the red 
coral of commerce, the sea-fans and sea-pens, in which there 
are no calcareous septa, and in which the corallum has, as in 
the sea-fans and sea-pens, a bony axis, while the fleshy por- 
tion (coenosare) represents the mesoderm and is filled with 
calcareous spicules. 
In the genera Haimea, Alcyontum, Tubipora, etc., the 
polyps are encrusting, budding out in different ways, and. 
adhere to foreign bodies by the ccenenchyma. Haimea is: 
simple, consisting of but a single polyp. In Aleyonium 
the ccnenchym is much developed, soft, lobulated, and. 
branching. Our common species is A. carnewm Agassiz. 
In Tubipora the polyps are compound and secrete solid. 
calcareous, bright red tubes, arranged side by side, like the: 
pipes of an organ, and supported by horizontal plates. 
In the common red coral (Corallium rubrum) of the 
Mediterranean Sea, the solid, unjointed coral-stock has a. 
thin cortical layer of spicules into which the polyps are re- 
tractile. The bright-red coral is worked into various orna- 
ments. The coral fishery is pursued On the coasts of Algiers 
and Tunis, where assemble in the winter and spring from 
two hundred to three hundred vessels. The coral-fishermen,. 
with large rude nets, break off the coral from the submerged 
rocks. About half a million dollars’ worth of coral is annu- 
ally gathered. 
Heliopora, now proved by Mr. H. N. Moseley to be an 
Aleyonarian instead of an Actinoid polyp, differs from 
Corallium and Tubipora ‘‘in that the hard tissue of its 
corallum shows no signs of being composed of fused spic- 
ules.” This genus, together with Polytremacis and the 
