REGENERATION IN MANCASELLUS MACROURUS. IO9 



hours later they were examined and twenty found to have 

 moulted. These twenty were isolated for another twenty-four 

 hours. At the end of the second day, that is, not more than 

 forty-eight hours after their last moult, twelve individuals of 

 about the same size from this twenty were operated upon. Thus 

 a double check was made on the size of the specimens for only 

 those whose length, both before and after the moult was about 

 he same, were retained. Three series were used. In series E 

 the right sixth walking leg was removed to again establish a 

 " standard " series. 



In the other two series " added " injury was also inflicted. The 

 removal of right fifth and fourth walking legs constituted this 

 " added " injury in series F and all right walking legs in series G. 

 In the above manner twenty-one individuals were selected and 

 operated upon on the twenty-sixth, nine on the twenty-seventh 

 and eighteen on the twenty-eighth, giving a completed series of 

 sixty individuals, twenty to a series. These series were main- 

 tained in the same manner as Set I., save that the water was 

 changed daily. The method of operation was also the same. 

 Two days after their next moult the isopods were killed. By 

 February 11, 1907, twenty-eight had moulted and the set was 

 discontinued. 



III. Data. 



The length in millimeters of the body, the original leg and the 

 regenerated leg is given for each individual that had regenerated 

 at the close of the experiment. The specific amount of regen- 

 eration, which is the per cent, of regeneration in terms of the 

 original leg is given for both sets. The specific rate, which is 

 the specific amount divided by the number of days in the moult- 

 ing period was obtainable only for Set II. 



Explanation of Tables. 1 



Set I. Series A. Right sixth walking leg removed. 

 Series B. Right 6-5 walking legs removed. 

 Series C. Right 6-5-4-3 walking legs removed. 

 Series D. Right 6-5-4-3-2-1 walking legs and cheliped removed. 

 Set II. Series E. Right sixth walking leg removed. 

 Serses F. Right 6-5-4 walking legs removed. 

 Series G. Right 6-5-4-3-2-1 walking legs removed. 

 1 Abbreviations : Orig., original ; Reg., regenerated ; Spec. Amt., specific amount ; 

 Spec. Rate, specific rate ; 13 -)-, moulted during last half of thirteenth day. 



