A HARD-SHELL CRAB CONVERTING ITSELF INTO A SOFT-SHELL 



The difference between a hard-shell and soft-shell crab is simply one of time. Every 

 now and then the crab needs to grow a little, so its body gets soft and its hard shell splits 

 open. It is then enabled to pull itself out of that shell and to grow while a new one is in the 

 process of forming. When this process is completed, it ceases to be a soft-shell crab and 

 once more joins the ranks of the hard-shells. This change takes place several times a season. 



uance unless some practical outcome is 

 shown or reasonably sure of accomplish- 

 ment. 



Fortunately, the Bureau of Fisheries 

 has from the outset been recognized as 

 an institution whose scientific investiga- 

 tions and experiments lead to important 

 practical ends, and the liberal appropria- 

 tions for this purpose made by Congress 

 year after year are an evidence of the 

 way in which the lawmakers regard this 

 service. 



Our artificial propagation of food 

 fishes, which is the most extensive work 

 of the Federal fishery bureau, has reached 

 its present proportions and efficiency en- 

 tirely through the application to hatch- 

 ing and rearing methods of biological 

 knowledge of the spawning, development, 

 and general natural history of each of 

 the fishes handled — knowledge that has 

 depended on painstaking, long-continued 

 field investigations. 



=;6o 



