CLASSIFICATION. 29 



Fourth Great Division. Animalia Radiata Radiated Ani- 

 mals or Zoophytes. 



A symmetry in the disposition of the organs of motion and 

 of the senses, which are placed in rays around a centre ; op- 

 posite faces of the body similar ; no distinct nervous system, 

 nor organs of sense; respiratory organs situated upon the 

 surface of the body ; circulation hardly discoverable in the 

 greater number ; a sac without issue for intestines. 



Division of Zoophytes into Four Classes. 



FIRST CLASS. ECHINODERMATA. 



Body invested with a well formed skin ; having a sort of 

 skeleton armed with points or movable spines ; an internal 

 cavity and a sort of vascular system, with distinct organs of 

 respiration. 



SECOND CLASS. ENTOZOA OR INTESTINAL WORMS. 



Body in general elongated ; no tracheae, branchiae nor other 

 respiratory organ ; no trace of true circulation; some vestiges 

 of nerves. 



THIRD CLASS. POLYPI. 



A small gelatinous body, often without other organ than a 

 cavity ; mouth surrounded with tentaculse ; propagation of 

 new individuals by shoots and eggs. 



FOURTH CLASS. INFUSORIA. 



Little microscopic beings swarming in stagnant waters ; 

 chiefly gelatinous, -and without viscera. 



