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The Regeneration of an Antenna-like Organ in Place of the 

 Vestigial Eye of the Blind Crayfish. 



By Charles Zeleny. 



(Abstract. ) 



The right eye stalk was removed in nine specimens of the blind 

 crayfish. A year after the operation three were alive. Two of these 

 showed no regeneration, but the third had developed an antenna-like 

 organ in place of the removed one. The new organ consists of a slender 

 feeler-like process covered with hairs and has the appearance of a func- 

 tional tactile organ. The terminal third is unsegmented but the basal 

 two-thirds is divided into segments. 



The result is of interest because it furnishes the only instance as 

 far as I know of the development of an apparently functional organ in 

 place of a removed non-functional one. 



