REGENERATION OF CRAYFISH 

 APPENDAGES. 



INTRODUCTION. 



The results embodied in this paper were obtained from ex- 

 periments carried on continuously from October, 1896, to June, 

 1901. The work was begun under the direction of Professor 

 Howard Ayers in the Zoological Laboratory of the University 

 of Missouri, and was completed under Professor George 

 Lefevre. 



I am indebted to Professor Ayers for direction and advice 

 during the first three years of the investigation, and to Professor 

 Lefevre for many valuable suggestions afterwards. I also wish 

 to express my appreciation of assistance given me by Professor 

 E. G. Conklin, of the University of Pennsylvania, in making 

 making certain revisions of the work, and by Dr. Charles Thorn 

 and Dr. C. M. Jackson in the preparation of material. 



Note: The publication of the present paper, practically completed in 1901, was at 

 first postponed in order to incorporate in it the results of certain experiments which were 

 at that time still in progress. Since the conclusion of these experiments, circumstances 

 which have been unavoidable have unfortunately made it necessary to further delay the 

 final appearance of the paper. George Lefevre. 



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