214 



THE RISE OF ANIMAL LIFE 



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Fig. 11-13. Life history of the lobster. 



path of this outgoing water current, the 

 waste products from these organs are also 

 carried away. 



Excretory system. Nitrogenous wastes are 

 withdrawn from the blood and body fluids 

 by a pair of kidneys, called the green 

 glands because of their color. They are 

 located beneath the antennae in the body 

 and consist of a glandular portion and a 



bladder (Fig. 11-11). The bladder stores 

 waste material until it is released through 

 the opening at the base of the antennae, 

 already referred to. 



Reproductive system. The gonads diflFer 

 slightly in shape in the lobster and the 

 crayfish; they are longer and thinner in the 

 former and fused into a three-lobed gland 

 in the latter (Fig. 11-11). Sperm cells are 



