94 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. 



similarity in the form of the polyps of any one species, 

 the shape of the colour has wide limits of possible 

 variation, and consequently a definition of it is almost 

 impossible. 



In other respects, too, the species vary. The colour, for 

 example, is sometimes constant, but more generally sub- 

 ject to considerable variation, and the spicules, which are 

 often very characteristic in form, more frequently are 

 subject to modification in size and form from that which 

 is regarded as typical of the species. 



The reproduction of the Alcyonarians is remarkably 

 constant. A few species are viviparous, the young being 

 born as solid, oval, ciliated larvse, which swim away and 

 then settle down to found a new colony. In the majority 

 of cases, however, the eggs and sperms are discharged 

 into the water simultaneously by the male and female 

 colonies, fertilisation is effected in the water, and solid 

 oval embryos are produced similar to those of the 

 viviparous species. No other larval form is known in the 

 group, and nothing occurs in the development of any 

 species of the nature of an alternation of generations. 



With the exception of the Precious Coral, the axis of 

 which is used by jewellers, none of the Alcyonarians have 

 any market value. Nor do the Alcyonarians, so far as 

 we know at present, form an important article of food for 

 fish or indeed any other marine animals. It is true that 

 occasionally fragments of Pennatulids are found in the 

 stomachs of Codfish, but there is no reason to believe that 

 they form a frequent nor a favourite diet." It is possible 

 that at the spawning period of the Alcyonarians many of 

 the eggs and embryos are devoured, but of this there is at 

 present no definite evidence. 



* The Haddock is sometimes found with pieces of the Pennatulid 

 Virgularia in its stomach. Vide A. M. & W. F. Marshall, Report on the 

 Oban Pennatulida, Birmingham, 1882. 



