ALCYONARIA ALCYONACEA 



347 



short distance at the base. Young Xenia colonies are in fact 

 Stolonifera in all essential characters. In Telesto prolifera we 

 find a network of stolons encrusting coral branches and other 

 objects after the manner of the stolons of many species of Clavu- 

 laria, although the zooids do not arise from these stolons singly, 

 but in groups, with their body- walls fused together for a certain 

 distance. In Telesto rubra the 

 spicules of the body-walls are fused 

 together to form a series of per- 

 forated tubes very similar in some 

 respects to the tubes of Tubipora. 



A remarkable genus is Coelo- 

 gorgia. Here we find a branching 

 colony arising from a basal stolon, 

 and the axis of the main stem and 

 of each branch consists of a single 

 very much elongated zooid bearing 

 on its thickened walls the branches 

 of the next series and other zooids. 

 It is true that in this genus there 

 is very little fusion of neighbour- 

 ing zooids, and the amount of true 

 coenenchym is so small that it can 

 hardly be said to exist at all. 

 Bourne l has united this genus with 

 Telesto into a family Asiphonacea, 

 which he joins with the Penna- 

 tulida in the order Stelechotokea ; 

 but their affinities seem to be closer 

 with the Alcyonacea than with the Fia , ^-Aicyonium digitatum, a 



J # t single-lobed specimen, with some of 



Pennatulacea,from which they differ the zooids expanded. 

 in many important characters. 



The genus Alcyonium not only contains the commonest 

 British Alcyonarian {A. digitatum), but it is one of the most 

 widely distributed genera of all Alcyonaria that occur in shallow 

 water. 



The genera Sarcophytum and Lobophytum occur in shallow 

 water in the tropics of the old world. The former frequently 

 consists of huge toad -stool shaped masses, soft and spongy in 



1 G. C. Bourne, Lankester's Treatise on Zoology, pt. ii. 1900, "Anthozoa," p. 26. 



