w 



Wadi (Wady) 



A watercourse in deserts, dry except after rains, term 

 used in southwest Asia and the Sahara, cf. Arroyo, Wash. 



Wallace's Line 



The line established by A. R. Wallace (1860) as a 

 boundary between the Oriental and the Australian Faunal 

 regions (q. v.). 



Warm-bloodedness 



See Honuoio therm. 



Warm Front 



The border between a mass of warm air advancing into 

 or above a mass of colder air. cf. Cold front. 



Warning Coloration 



See Aposematic. 



Wash 



In southwestern United States, a dry bed of an inter- 

 mittent stream, usually sandy and gravelly. 



Wasting Disease 



A disease of eelgrass (Zostera marina) often producing 

 serious epidemics, caused by a Slime mold (Labyrinthula sp.). 



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