loS Papers from the Marine Biological Laboratory at Tortugas. 



periods and the amounts of regeneration of the propodite of the right chela 

 in all valid cases are taken. For the first regeneration period these data 

 are given in order of length of the molting period in table 6 and the same 

 data are plotted in coordinate form in table 7. Tables 8 and 9 give corre- 

 sponding data for the second regeneration period. An examination of these 

 tables makes it evident that there is but a slight degree of correlation be- 

 tween the length of the molting period and the amount of regeneration. 

 The amount of regeneration which takes place during a molting period is 

 determined only to a very slight extent by the length of that period. It 

 seems, therefore, that the regeneration takes place for the most part during 

 the early days of a molting period and very little increase in size occurs 

 during the later days. For this reason it is not possible in determining the 

 rate of regeneration to use the absolute number of days during which re- 

 generation has taken place. 



(c) Correlation betivecn the ccphalo-tlwracic length and the amount of 

 regeneration of the right chela. — The cephalo-thoracic lengths and the 

 amounts of regeneration of the propodites of the right chelae in all valid 

 cases are taken. Table 10 gives these data arranged according to cephalo- 

 thoracic length for both the first and the second regeneration periods. The 

 specific amount of regeneration, that is, the amount divided by the cephalo- 

 thoracic length, is added for each individual. The individuals with a second 

 regeneration are put as nearly as possible opposite individuals of the same 

 size with a first regeneration. For the first regeneration period the data are 

 further shown in coordinate table iia and for the second regeneration in 

 coordinate table 12. For both periods it is evident that there is a very close 

 correlation between the size or age of the animal and the amount of regen- 

 eration of its right chela. With an increase in size there is thus a pro- 

 portionate increase in the amount of regeneration that takes place during a 

 molting period. This amount of regeneration is independent of the length 

 of the molting period, as has already been shown in the last section. 

 Therefore, in comparing the successive regenerations of the right chela, it 

 is found best to use the molting period as a unit without regard to its length. 



A study of tables 10, iia, and 12 shows a further point of interest re- 

 garding the relation between the size of the crab and the amount of regen- 

 eration of its right chela. It is seen that as we go from the smaller to the 

 larger individuals the amount of regeneration increases proportionately 

 faster than the size of the animal. In tables iia and 12 the dotted line 

 is the line of average specific amount of regeneration, that is, the line along 

 which all the measurements would be arranged in case the specific amounts 

 were the same for animals of all sizes. It is seen that for the smaller indi- 

 viduals the measurements of regeneration-length come below the line and 

 for the larger ones above it. Thus the larger individuals show propor- 

 tionately a greater amount of regeneration than the smaller ones. This 

 result is undoubtedly to be correlated with the fact that there is a correspond- 

 ing proportionate increase in the size of the chela in uninjured individuals. 



