STRUCTURE OF ZOOPHYTES. 88 



these organs of motion, the animal is enabled to move itself 

 from place to place. Some of the animals of this order are 

 composed of several branches united together in one com- 

 mon centre, like the spokes of a wheel ; and hence they are 

 called star-fish, or more commonly five-fingers. Their mouth 

 is in the centre, where the several branches meet. Others are 

 globular, and others oblong, like the sea-urchin and sea-egg. 



The Intestinal Worms belong also to the class of Zoophytes. 

 Those \vhich inhabit the bowels of children are well known. 

 But there is scarce any animal which is not infested by one 

 or more kinds of them. They can exist only within the bodies 

 of the animals to which they belong, and it is seldom that the 

 same species infests more than one kind of animal. They 

 have no visible organs of respiration or circulation, and those 

 of digestion are very imperfect and indistinct. They are not 

 confined to the intestines, but are found in other canals and 

 passages of the body, and even in the substance of parts, as 

 in the liver, brain, and eye. The difficulty of accounting for 

 their existence in these parts, has given rise to the opinion of 

 some naturalists, that they are spontaneously engendered ; 

 but it is known, with regard to many of them, that they pro- 

 duce eggs, and a living offspring ; and it is contrary to all the 

 analogy of nature to ascribe, in these obscure cases, to chance 

 and the spontaneous operations of matter, the production of 

 effects, which, in all other instances, are the result of a per- 

 fect and wonderful adaptation of organs to the end in view. 



The Sea-nettles, or Sea-anemones, are still less perfect. 

 Their bodies are circular, and in their centre is the mouth, 

 which leads to several rude and imperfect cavities in the sub- 

 stance of the animal, answering the purposes of stomach and 

 intestines. They are generally found attached by their base 

 to some rock or marine substance ; but this attachment is vol- 

 untary, for they can at will disengage themselves. Generally, 

 however, they perform no other motion than that of opening 

 and closing their mouths, and extending the tentacula with 

 which they are surrounded. With these they grasp animals 

 coming within their reach, such as small fish, mollusca 

 worms, &c. These they swallow, and after having digested 

 their flesh, throw out their bones, shells, and other refuse 

 matter by the same opening, which is their only one. 



The Medusae do not differ much from these, except that they 

 are merely of a gelatinous, slimy consistence, and are never 

 found fixed by their base. They are common, and are often 

 seen in immense shoals. One species of them is vulgarly 

 known by the name of sun-fish. 



