KATE OF GROWTH OF THE AMERICAN LOBSTER. 



235 



very natural environment, and rendered it easy to make observa- 

 tions at any time. The facts concerning the development of the 

 early stages may be more tangible when presented in the fol- 

 lowing table : 



WICKFORD LOBSTERS. 



Total average 18.3 



WOODS HOLE LOBSTERS. 



Total average 15.3- 



1 The fifth stage-period is often shorter than the fourth because the water at Wick- 

 ford is usually the warmest during the fifth stage-period. 



2 This percentage is greater than in the case of another group of 66 lobsters in 

 which Herrick obtained a result of 13.67 per cent. 



The foregoing demonstrates the fact that the average stage- 

 period of the Wickford lobsters is less than the stage-period of 

 the Woods Hole lobsters. Further that, while the percentage of 

 increase at each molt for the Woods Hole lobsters (kept in 

 aquaria) was only 13.5 or 15.3, the amount of increase for the 

 Wickford lobsters was over 18 per cent, in the individuals recorded 

 above, while in the case of a group of individuals which had been 

 especially selected (/. e., the smaller and weaker specimens were 



