PLATE XVI. 



FIG. 130. 



FIG. 129. 



A, female of Cyclops quadricornis ; a, body ; 6, tail ; 

 c, antenna ;'d, antennule; e, feet; /, plumose setae of 

 tail ; B, tail, with external egg-sacs ; c, D, E, F, G, 

 successive stages of development of young. 



FIG. 131. 



Metamorphosis of Carcinus mcenas: A, first stage ; B, second stage ; c, third stage, 

 in which it begins to assume the adult form ; D, perfect form. 



