DIVISION IV.— RADIATA, or ZOOPHYTES. 



This division includes the most simple forms of animated nature, 

 and although these forms vary considerably in the several classes, 

 all show traces, more or less distinct, of radiation from a common 

 centre. 



It includes five classes. 



Division. Class. 



I. ECHINODERMATA 



II. Entozoa, or, Intestinal Worms 



RADIATA.. < III. AcALEPH^ 



IV. Polypi 



V. Infusoria 



CLASS I.— ECHINODERMATA. 



This name is strictly applicable to the genus Echinus, sea-urchins, 

 or hedgehogs, but is applied more generally to the most complicated 

 of the radiated animals. All the genera have a well organized skin, 

 with, distinct viscera, and a sort of imperfect vascular system. 



The class includes two orders. 



ECHINODERMATA. . < g 



Pedicellata 

 2. Apedicellata 



ORDER I. — Pedicellata. 



The envelope in this order is pierced with apertures, through 

 which issue numerous membranaceous tentacula, which acting as 

 organs of motion, are called the feet. 



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