CCELENTERATA : CAMPANULARIDA. 



125 



ORDER IV. CAMPANULARIDA. The members of this order 

 are closely allied to the Sertularida ; so closely, indeed, that 

 they are very often united together into a single group. The 

 chief difference consists in the fact that the hydrothecae of the 

 Campanularida^ with their contained polypites, are supported 

 upon conspicuous stalks, thus being terminal .in position (figs. 

 46, b, and 50) ; whilst in the Sertularida they are sessile or sub- 





Fig. 50. Portion of the colony of Clytia (Campanularia) Johnstoni, magnified. 

 . p Nutritive zooid ; g Capsules in which the reproductive zooids are produced. 



sessile, and are placed laterally upon the branchlets. The 

 gonophores also in the Campanularida are usually detached as 

 free-swimming medusoids, whereas they remain permanently 

 attached in the Sertularians. Each medusoid consists of a 



