SOME ABNORMALITIES AND REGENERATION 



OF PLEIOPODS IN CAMBARUS AND 



OTHER DECAPODA. 1 



CHARLES ALBERT SHULL. 

 INTRODUCTION. 



The two crayfishes whose abnormal appendages are described 

 in this paper were found among a small number of specimens of 

 Cauibarus virilis Hagen, which were captured near the city of 

 Chicago in the autumn of 1904. The discovery of these abnormal 

 pleiopods led to an experimental study of the regeneration of the 

 abdominal appendages in the crayfish, the results of which are 

 given herein. The earlier experiments were unsuccessful owing 

 to imperfect methods of handling the material, and to the use o 

 mature animals in which the moults were infrequent. The later 

 experiments, with improved methods of caring for the material, 

 and with small immature specimens, have yielded satisfactory 

 results. 



These experiments were begun in the Hull Zoological Labora- 

 tory of the University of Chicago, continued in the Biological 

 Laboratory of Transylvania University, and completed in the 

 Marine Biological Laboratory of the Brooklyn Institute of Arts 

 and Sciences at Cold Spring Harbor, Long Island. I wish to 

 express my thanks to Dr. Davenport, director of the Marine 

 Laboratory, who kindly placed the facilities necessary for the 

 completion of the work at my disposal ; also to Dr. A. E. Ort- 

 mann, of the Carnegie Museum, Pittsburgh, to whom I am in- 

 debted for identification of the species used in the experimental 

 work ; and to Dr. Faxon, of Harvard, and to Dr. Hans Przibram, 

 of Vienna, for examining the abnormal specimens. 



HISTORICAL SUMMARY. 



The regeneration of the abdominal appendages of decapod crus- 

 taceans has been a subject of investigation for many years, but 



'Contributions from the Biological Laboratory of Transylvania University, No. 2. 



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