354 G. G. SCOTT. 



pears clear that it is hardly correct to assign the carrying of pure 

 air to one set of tracheoles in the gill and the carrying of impure 

 gas to the other set of tracheoles. A detailed examination of 

 the tracheal system demonstrates not only its complexity but its 

 many interconnections and therefore its unity. It may be re- 

 garded as the lungs of the animal whose branches ramify 

 throughout the body, present in every tissue, carrying oxygen 

 to every cell directly and returning the products of respiration 

 from the tissues to the exterior. It is an arrangement admirably 

 adapted to an organism leading a very active life much more 

 active than that of many of the higher forms. 



G. G. SCOTT. 

 COLLEGE OF THE CITY OF NEW YORK. 



LITERATURE CITED. 

 Chun. 



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Dewitz, H. 



'go Eininger, Beobachtungen betreffend das geschlossene Tracheensystem bei 

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