GENERAL FEATURES OF WATER EXCHANGES 



189 



The positions of equilibrations are indicated on the arbitrary 

 basis of the initial 1.0 hour of adjustment. At 0.1 hour by the clock 

 or during 2 hours by the clock, at other temperatures or during 

 other manipulations, the positions would be otherwise. 



Perhaps the general feature of first note is that each of the 

 species studied has a means of adjusting excesses, and a means of 

 adjusting deficits. The two means or paths are usually structur- 



TABLE 17 



Paths of water exchanges in various genera, t = terrestrial ; s-seawater; r = freshwater. 



Parentheses indicate paths that are available and used only under special 



conditions. Information from many sources 



S ^ 2 g 

 O !;t Eh ft^ 





^ ti ;? 



C3 rO 



^ ^ Ah !^ 



^ Rh 



« -:. e 



^ S SS 



s, -.^ o *- 



t^ Cq O ^ 



Environment 



Paths of water 

 gain: 



Mouths 



Intestines 



Anal gills 



Opercular gills ... 



Surfaces 



(osmosis) 



Surfaces (con- 

 densation) 



Food vacuoles 



Chemical forma- 

 tion 



Emunctories : 



Kidneys 



Nephridia 



Antennal glands 

 Coxal glands 



Malpighian 



tubules 



Mouths 



Intestines 



Water vascula 



Lungs 



Opercular gills ... 



Trachea 



Surfaces 



(osmosis) 



Surfaces (evapo- 

 ration) 



Contractile vacu- 

 oles 



Sweat glands 



Mucous glands ... 



t t t r 



XXX 



X X X X 



X X X X 



X X X X 



X X X X 



(X) 



(^) 



s t t t 



X X X X 



X X X X 



(^) 



t r r 



X X X X 



X X (x) X 



X X 



X X X X 



(^) 



(X) 



