56 REPORT OP^ COMMISSIONERS OF INLAND FISHERIES. 



ment is without doubt more strongly affected by environmental cir- 

 cumstances, it being probable that the sexual maturity is not reached 

 before the fourth or fifth year of the lobster's life. Thus, with the 

 scant data in hand, no facts can be positively asserted with reference 

 to the change in form between the seventh and twelfth stages. The 

 average length of the lobsters for these later stages is as follows : 



5th stage 15+ mm. 



6th stage 18^ " 



7th stage 22^ " 



8th stage 26^ " 



9th stage 32 



10th stage 38 '' 



11th stage : 43 



II. The Pigmentation of the Lobster and the Color 



Changes in the Successive Stages. 



The study of the coloration in members of the class Crustacea, 

 owing to the beauty and great variation in color, and to the physi- 

 ological importance of the question of its nature, development, and 

 function, has at all times proved an attractive field for the biologist. 

 Yet unfortunately, to within a few years at least, it has been a field 

 too fully overrun with speculation and too wholly unfrequented 

 by the direct experimental results which can be gained from investi- 

 gation upon many forms of both lower and higher Crustacea. No 

 doubt the desire to discover in many observed results the phenomena 

 of natural selective tendency, in order to explain thereby the value 

 and constancy of certain color markings and variations, has been 

 responsible, in some measure at least, for the infrequency of definite 

 lines of experimentation upon the conditions of color variation. 

 When such experiments have been made, however, as in Cunning- 

 ham's investigations upon the color of young flounders, environ- 



