MancJiester Memoirs, Vol Ix. (19 16). 11 



unable to adapt its method of growth according to the 

 nature of its support, the number and character of its 

 neighbours in the immediate vicinity, and according to 

 the set of the currents and the food they bring, the species 

 would soon be come extinct. 



With this great plasticity in the method of growth 

 and therefore the great accommodation of shape to the 

 conditions of the environment many of the characters 

 used by systematists for the distinction of species must 

 be regarded as of very little value. In many of the 

 genera of corals and alcyonaria I am convinced that there 

 is no series of discontinuous groups comparable with the 

 species of bilaterally symmetrical animals, and I think it 

 is very probable that when we have further detailed infor- 

 mation concerning the range of variations of various kinds 

 of Coelenterate sedentary colonies the attempt to sub- 

 divide the genera into definite specific groups will be 

 finally abandoned. 



If this general conclusion is justified it must be 

 admitted to be one of far-reaching importance, because it 

 will necessitate a very different treatment of the systematic 

 zoology of many groups of Coelenterata to that which is 

 generally adopted ; but after many years of laborious 

 work in striving to determine species of these animal 

 colonies I feel quite convinced that we have been engaged 

 in a more or less fruitless task. In some of the genera to 

 which I have paid special attention, such as Millepora, 

 Tubipora, Spongodes (Dendronephthya), Solenocaulon 

 and some others, the evidence afforded by the examina- 

 tion of a large number of specimens from different localities 

 affords no support to any conception of discontinuous 

 species, and in others, such as Stylaster r Errina, Disticho- 

 pora, Alcyonium, the number of species could safely be 

 reduced to two or three. 



