Rate of Regeneration. 361 



individuals of one sex in a series and is equal in the two series. 

 (See Tables VI and VII, pp. 357 and 358.) The amount of 

 regeneration of the right chela at the end of the first moult is 

 therefore the same no matter what the degree of injury may be. 

 The average specific amount of regeneration for the males of 

 Series A at the end of the first moult is .444 ( ±.003). For the 

 males of Series B at the same time it is .435 ( ±.006). The differ- 

 ence between the two is just equal to the sum of the probable 

 errors and therefore cannot be considered as significant. Like- 

 wise the females of Series A have an average specific amount of 

 regeneration equal to .400 ( ±.006) and those of Series B an aver- 

 age of .403 ( ±.004). The difference is less than the sums of the 

 probable errors and is therefore not significant. 



These results show very definitely that the specific amount ot 

 regeneration of a removed chela at the end of the first moult after 

 the operation is a constant which is not affected by the time ot the 

 moult, the size of the animal, or the degree of other injuries to the 

 individual. Four of the individuals, which moulted very soon after 

 the operation, three within the first day and one in three days, are 

 not included in this statement. None of the individuals moulted 

 in the interval between three and twenty-seven days after the 

 operation so that it is not possible to say to what degree the state- 

 ment holds true for this period. For all periods above 27 days 

 up to 181 days when the experiment was closed the specific 

 amount of regeneration is a fairly constant quantity for the first 

 moult after the operation. 



Specific Rate of Regeneration. 



The specific amount of regeneration of the right chela divided 

 by the number of days between the date of operation and the first 

 moult gives the specific rate of regeneration. The specific rate 

 of regeneration is the amount of regeneration per unit ot thoracic 

 length per day. 



The average specific rate of regeneration of the two chelae in 

 the series with the greater injury (Series B) is greater than that 

 of the one removed chela in Series A. This is brought out very 

 definitely in Tables VI and VII (pp. 357 and 358). For the males 

 the values of the specific rate are .0049 ( ±.0003) for Series A and 

 .0080 ( ±.0005) for Series B. For the females the corresponding 



