Feaon * 
No. XVII.—ANTIPATHARIA. 
By C. Forster Coorgr, .4., Trinity College, Cambridge. 
(Communicated by J. Stanuey Garpiner, M.A., F.R.S., F.L.S.) 
(Plate 41 and 27 Text-figures.) 
Read 7th May, 1908. 
Tue present collection consists of the specimens obtained on board H.M.S. Sealark, 
together with some collected by Colonel Alcock, F.R.S., in the more northerly parts of 
the Indian Ocean and by him kindly forwarded to me for examination. I am further 
indebted to Professor G. C. Bourne for a specimen obtained by him in Diego Garcia, 
as well as for some obtained during the earlier cruises of the ‘Investigator.’ The 
forms are divided among the genera Cirripathes (1), Stichopathes (8), Bathypathes (1), 
Schizopathes (1), Aphanipathes (2), and Antipathes (10). 
In a collection containing a fair number of forms, such as this under discussion, it is 
not a matter of any great difficulty to separate them so that they fall into certain main 
groups. The number of the mesenteries, the presence of a simple or a branching axis, 
the unity or partial division of the polyp, and such like characters are of sufficient 
distinction to enable the forms to be placed definitely in the genera Cirripathes, 
Stichopathes, Antipathes and so forth. It is among the specimens that fall within 
these main groups or genera that the difficulty of separation arises. In fact we do not 
know what characters constitute or serve to diagnose a species in the Antipatharia. 
Such characters as we have to use are :— 
(1) Mernop oF GrowTH OF THE COLONY. 
The single coiled or whip-like form of the colony has already been used to distinguish 
the Indivise from the branched forms or Ramose. The question is, to what extent 
is the amount of coiling or flexion on the one hand, or of branching on the other, a true 
index of specific rank: or to what extent are they merely secondary phenomena produced 
by external agents, such as currents and other physical causes, acting on the growing 
colony ? Schultze quotes the extent to which Savaglia may be altered in its growth 
by such an agency as the sweeping action of nets used by coral fishermen in the 
Mediterranean. It is reasonable therefore to suspect that great modifications are 
produced by various physical conditions, especially by currents, and also to some degree 
by light, by the presence or absence of mud and silt in suspension, by the nature of the 
bottom on which the colony grows, and so on. 
