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ANIMALIA RAD I AT A. 



ORDER I. NEMATOIDEA. 



An intestinal canal floating in a distinct abdominal cavity; 

 a mouth ; external skin furnished with muscular fibres. The 

 Ascaris belongs to this order. 



ORDER IL PARENCHYMATA. 



Body inclosing in its parenchyma viscera indefinitely ter- 

 minated, and resembling most frequently vascular ramifica- 

 tions, sometimes none apparent. Example, the Tsenia. 



ACALEPHA. 



Marine animals, in whose organization we still perceive 

 vessels, although Cuvier regards them as productions of the 

 intestines excavated in the parenchyma of the body ; form 

 circular and radiated ; a single orifice ; no distinct organs of 

 respiration. Their name, derived from the Greek, signifies 

 nettle, and has been given to them on account of the faculty 

 possessed by certain species of imparting to the hand which 

 touches it a sensation of pricking and burning. Two orders. 



ORDER I. SIMPLICIA. 



Natation effected by means of the contractions of the body ; 

 some emit a phosphorent light, making the sea, at night, re- 

 semble a starry sky ; substance gelatinous ; no fibres apparent. 

 Example, the Medusa. 



