xliv 



INTRODUCTION. 



As amongst plants, some species are annuals, especially 

 such as are parasitic on the fronds and stems of seaweed, 

 while others are probably perennial. The large, arbores- 

 cent masses of the stouter kinds of Sertularia, Halecium, 

 Eudendrium, &c. must be the growth of several seasons. 

 Van Beneden has seen specimens of Tubularia and Cam- 

 panularia live for several years in an aquarium without 

 any diminution of their vegetative activity. The medusi- 

 form zooids, the vagrant members of the colony, are com- 

 paratively shortlived ; their function is seasonal, and as 

 soon as it is fulfilled they perish*. 



It seems to be not improbable that the polypites in 

 some cases perish in the winter, like the leaves of decidu- 

 ous plants, and are renewed with the return of spring. 

 Lamouroux states that he had found this to be the case in 

 some species; and Lieut. Thomas, in a note on Euden- 

 drium ramosum, records the fact that at Alloa, where this 

 zoophyte is abundant, no specimens were found "with 

 ' heads ' on in the month of November " f. Dr. Strethill 

 Wright, too, as mentioned before, has seen many speci- 

 mens of Hydr actinia in which the coenosarc was fully 

 developed in winter, but the polypites were few in number 



continually shed, and in consequence thousands of new colonies established, 

 their multiplication becoming so great during a favourable season that the 

 rocks literally appear clothed with the yellow stems and rose-coloured blos- 

 som-like bodies of these flower-animals." G-ymnophthalmata of Charleston 

 Harbour, Proc. Elliott Soc. Charleston, vol. i. 



* "Dans les plantes comme dans les auimaux, la vie est generalernent 

 longue et la tenacite grande dans les individus agames ; ephemere et delicate, 

 an contraire, dans les individus sexues. L'analogie entre la mednse et la 

 fleur so confirme de plus en plus." Fan Ben. Polypes, p. 101. 



t Supplement to Johnston's ' British Zoophytes,' p. 467. 



