Growth, and Habits^ of Coral Zoophytes. 39 



panded with the mouth wide open to receive their prey. As 

 they are fixed to the rocks, they must wait for their food to 

 come to them. When a crab, shell fish, or any thing alive, 

 within the capabilities of their bodies, comes within reach, 

 they usually secure it by closing upon the victim the tenta- 

 cles (which commonly have a stinging power), and pushing 

 it into the mouth. In many species the tentacles are too 

 short to aid in capturing food except it be by stinging. These 

 organs subserve also the purpose of aerating the blood, a 

 function in which all parts of the body are more or less 

 concerned. 



The interior of the actinia contains a cylindrical stomach 

 suspended from the disk, which opens at bottom into the gene- 

 ral cavity of the body. This general cavity, below the sto- 

 mach and around it, is divided into compartments by radiating 

 fleshy lamellae, the larger of which in their upper part connect 

 the stomach with the sides of the animal. The most im- 

 portant function of these lamellae is that of reproduction, 

 some being spermatic, and the others bearing clusters of ova. 

 These ova leave the body by passing out through the stomach 

 and the mouth ; but in many instances this does not take 

 place till the young animal has proceeded from them. The 

 refuse from the food after digestion in the stomach is also 

 ejected by the mouth, as this is the only opening to the 

 alimentary cavity. Other excrementitious matters, separated 

 on the final elaboration of the chyle and its assimilation, may 

 escape through the sides of the animal, the openings at the 

 extremities of the tentacles, or in general by whatever pores 

 or passages water may be ejected in the contraction of the 

 animal. 



One of the most singular peculiarities of polyps is their 

 ready restoration of a lost part. Even a fragment will go 

 on to complete the entire animal again ; as with the fabled 

 hydra of old, the knife is used but to multiply, for every sec- 

 tion becomes a new animal. 



In all the points mentioned in the description here given, 

 the polyp of ordinary coral and the actinia are identical. 



b. Process of Budding, — There is one mode of reproduction 

 which, although having no necessary connection with coral 



