POLYPI. 513 



CLASS IV. 

 POLYPI. 



Our fourth class of the Radiata, or Zoophytes has been thus 

 named because the tentacula which surround their mouth give them 

 a slight resemblance to an Octopus called Polypus by the ancients. 

 The number and form of these tentacula vary. The body is always 

 cylindrical or conical, frequently without any other viscus than its 

 cavity, and frequently also with a visible stomach, to which adhere 

 intestines or rather vessels excavated in the substance of the body 

 like those of the Medusae; in this latter case we usually find ovaries 

 also. Most of these animals are capable of forming compound be- 

 ings, by shooting out new individuals, like buds. They are also, 

 however, continued by eggs. 



ORDER I. 

 CARNOSI. 



The first order comprises fleshy animals that usually fix them- 

 selves by their base, several of which, however, have the power of 

 crawling on that base, or even of detaching it altogether, and swim- 

 ming or suffering themselves to be carried away by the current. 

 Most commonly, however, they merely expand the oral aperture. It 

 is surrounded with a greater or less number of tentacula, and opens 

 into a stomach en cul-de-sac. Between this internal sac and the 

 external skin we find a tolerably complex, but still obscure organi- 

 zation, chiefly consisting of fibrous and vertical leaflets, to which the 

 ovaries, that resemble tangled threads, are attached. The intervals 

 of these leaflets communicate with the interior of the tentacula, and 

 it appears that water penetrates into and issues from them by small 

 orifices in the circumference of the mouth; the Actinias, at least, 

 sometimes ejaculate it in this manner. 

 3 P 



