188 



" Granny " Crabs). If a male, it will probably cast once 

 in two years. 



FIRST YEAR. 



SECOND YEAR. 



THIRD YEAR. 



FOURTH YEAR. FIFTH YEAR. SIXTH YEAR. 



SEVENTH YEAR. EIGHTH YEAR. NINTH YEAR- 



Number of Casting 15 



Width in mm 137'5 



Width in inches (5J) 



Did not cast 



16 

 171-8 



TENTH YEAR. ELEVENTH YEAR. TWELFTH YEAR. 



The approximate calculations given above do not 

 lend support to Williamson's statement that " a crab of 

 four and a quarter inches across would be not less than 

 three years, nor probably more than four years old." 

 Even if we take a growth ratio of one-third, which is 

 rather high, we find that the crab would not reach the 



