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PHILIP B. HADLEV. 



thrown out) the average amount of increase for the first ten stages 

 was 20.9 per cent. In tin's last instance the lobsters in the re- 

 spective stages were consequently much larger than those in the 

 group of Wickford lobsters tabulated above. Their average 

 measurements, however, are presented in the following table : 



These and other observations would demonstrate that there are 

 great variations in the rate of development of lobsters, not only 

 in different localities, and under different conditions of environ- 

 ment, but also in the same locality and under identical conditions. 

 Furthermore, that there is a tendency manifested in those indi- 

 viduals which are slightly above the normal in size and strength, 

 to increase the advantage which they have already gained. This 

 advantage, lodged in the fourth stage lobster, may be no more 

 than a millimeter, but this slight gain compounded through nu- 

 merous successive stages gives, even the tenth and eleventh stage, 

 a decided lead which is never again lost and which may be ob- 

 served in the last mentioned group. 



Continued observations upon the later stages (from the tenth 

 on) prove that not twelve to seventeen stages, as calculated by 

 Herrick, but an average of twelve stages are passed during the 

 first year of the lobster's existence. We may trace the future 

 development of the young lobster through the later successive 

 stages as follows : September finds the average individual, hatched 

 the previous June, in the ninth stage and with an average length 

 of 32 mm. He passes into the tenth stage in the latter part of 

 September, with a corresponding length of 37.9 mm. In the 

 latter part of October or the first of November he enters the 

 eleventh stage with an increase to 45 mm. Through the months 

 of November, December, January, February and March he lies 

 dormant, passing into the twelfth stage some time in April or the 

 first part of May. Thus it appears that a lobster one year old is 

 in the twelfth stage and has an average length of 53 mm. There 

 are always exceptions to this rule, - - instances where an individual 



