268 
BULLETIN OF THE UNITED STATES FISH COMMISSION 
THE ALCYONARI A. 
The order Alcyonaria includes those members of the class Anthozoa, Phylum 
Ccelenterata, characterized by the presence of eight pinnate tentacles and a corre- 
sponding number of mesenterial filaments or folds, with or without definite skeletal 
structures. All are of marine habit, and most are colonial, forming more or less 
complex clusters or groups of polyps united to a common stock. The buds which 
go to make up the colony arise usually from stoloniferous extensions of the body 
wall at the base of the polyp, or from disk-like expansions, containing nutritive 
canals which ramify through the more or less fleshy coenenchyma and which give 
rise to secondary stems, branches and sub-branches, often forming a very complex, 
dendritic structure more resembling a plant than an animal, as, for example, in the 
beautiful “sea-fans,” “ sea-plumes,” etc. Hence the term “Zoophyte,” by which 
the older naturalists designated them. 
Calcareous particles or spicules of an almost infinite variety of form are usually 
present in some part of the tissues, chiefly in the .so-called coenenchyma of the stem 
and branches, as well as in the tentacles and body of the polyps. They may occur 
somewhat promiscuously scattered throughout the tissues, or may be limited more or 
less to certain portions of the colony, or may become coalescent to form definite 
skeletal structures, as the axis of red coral or of the sea- fans. In certain forms, as 
the Oormdaridce, instead of calcareous spicules there may be a chitinous or horny 
secretion over the polyp walls and stolons. 
So remarkable a feature do these spicular bodies form that elaborate systems of 
classification have been based upon their peculiarities, including families, genera, 
and even species. Indeed, at present, it may be said that these form one of the chief 
taxonomic characters in general use. Some doubt has, however, been recently 
thrown upon this method, notably by Hickson , 1 who has shown that they are of a very 
variable nature, even under ordinary conditions of depth, temperature, etc. These 
variable conditions may greatly modify their size, form, and color — the very features 
which have been held to be of diagnostic importance. 
To some extent my own observations confirm those of Hickson, and I more than 
suspect that not a little revising of present categories of classification will be an early 
necessity. While among some groups there may be found a certain stereotyped 
form and size of spicular body, it does not seem to me that it can hold anything like 
the place of importance which has hitherto been claimed for it. 
The following synoptic table or key has been compiled from several sources, 
chiefly from Edwards and Haime, Histoire Naturelle des Coralliarres; Kolliker, leones 
Histologic*; Kukenthal, Alcyonaceen von Ternate; the Synopses of Broun, Klaseen 
und Ordnungen d. Thierreichs; Leunis, Synopsis der Thierkunde; Kent, on the 
Spicules of Gorgonacese; Wright and Studer, Report on the Alcyonaria of the 
Challenger Expedition, vol. xxxi. These have been supplemented by free refer- 
ence to special papers and descriptions and by such notes as have seemed helpful 
and available for the more ready determination of family, if not generic, relations, 
1 Report. Third International Congr. of Zoologists, p. 352. 
