REPORT OF COMMISSIONERS OF INLAND FISHERIES. 303 



The significance of these results is readily perceived from a com- 

 parison of the conditions involved. It will be recalled that, at the 

 beginning of the experiment, the lobsters in Group I and Group II 

 had molted to the fourth stage on the same day, July 21, and were 

 practically equal in size.* 



The specimens in Group I were kept in a normal condition, while 

 the specimens in Group II were mutilated after each molt. According- 

 ly, the only essential difference in the conditions between these two 

 groups of lobsters consisted in the fact that in one group the lobsters 

 were regenerating mutilated appendages, while in the other group 

 the lobsters were in a normal condition. Therefore it seems evident 

 that the introduction of the process of regeneration into Group II 

 has, in the course of 134 days, resulted in a difference of 10.5 per 

 cent, between the size of the regenerating and normal lobsters in 

 favor of the latter. 



It is evident that a closer comparison of the effect of regeneration 

 on the increase in size may be made by comparing corresponding 

 stages in the two groups of lobsters; for it may be observed that the 

 measurements for December 2 do not all represent the same stages. 

 For example, on December 2 lobster No. 49 was still in the eighth 

 stage, while most of the other specimens were probably in either 

 the ninth or tenth stages. Accordingly, a more exact comparison 

 can be obtained from the data for the fifth, sixth, and seventh stages, 

 in which every specimen was measured after each molt. For these 

 stages the Tables VII and VIII show the following averages : 



*(It may be noted that the length for the fourth stage are not given in the tables. When 

 these specimens were selected in the preceding experiments, they were all so nearly equal in 

 size that it was not thought necessary to measure each individual, and so unfortunately the 

 •exact fourth stage length for each specimen was not obtained. Some of the preserved fourth 

 stage specimens from Series B and Series C* to Ci3 were however, measured later, and the 

 average length was 13.9 mm.) 



