62 



ANTHOZOA. 



then becomes apparent that some of the animals, as described above, 

 terminate in tubular prolongations, whereof the general substance of 

 the polypary seems to be made up; others, however, sprouting im- 

 mediately from the parietes of the former, have their internal cavity 

 continuous with that of the larger central polyp, so that a free com- 

 munication is kept up between them (fig. 27, 1), the whole forming a 



Fig. 27. 



Anatomy of Alcyonidium elegans (after Milne-Edwards). 1. One of the branches of the 

 polypary opened to show the communication which exists between the abdominal cavity of the 

 principal polyp and the interior of the young ones sprouting therefrom : the apertures, it will be 

 observed, are always in the track of the longitudinal ovarian folds. 2. Lower portion of an 

 ovarian fold detached from the walls of the abdominal cavity to show the manner in which the 

 ovules or gemmae are developed. 3. A portion of the foot, or basilar portion of the polypary : 

 a, membranous tubes ; 6, spicula incrusting this portion of the polypary. 4. A spiculum magnified. 



sort of ramified tube, or an animal having one body and one central 

 stomach, but furnished with many heads and as many mouths. 



(133.) The development of these secondary polyps is effected by a 

 simple process of gemmation. A tubercle makes its appearance upon 

 the surface of the primary animal, which looks at first like a little 

 caecum appended to the integument, having no oral aperture, but com- 

 municating freely, by means of its central canal, with the abdominal 

 cavity of its parent. When arrived at a more advanced stage of de- 

 velopment, the tentacula make their appearance and the alimentary 



