231J REGENERATION OF CRAYFISH APPENDAGES 43 



an eye but either a short appendage that consists of one, two, 

 or three segments, or a longer structure consisting of either one 

 or a pair of antenna-like flagella. 



13. Before any regenerated part can assume a normal ap- 

 pearance it is necessary that a moult take place. Before a moult 

 the regenerated portions are much compressed and when re- 

 leased may expand to twice the proportions permitted by the 

 confining cuticle. 



14. The general results of this series of experiments sub- 

 stantiate the view that the power of regeneration is independent 

 of the liability of the part to injury. The results also show 

 that the rate of regeneration depends both upon external fac- 

 tors and the physiological condition of the animal operated upon. 



Zoological Laboratory, 

 University of Missouri, 

 June I, 1901. 



