THE LAW OF LIKENESS, AND ITS WORKING. 21$ 



through a metamorphosis, as the series of changes is named, 

 the law of likeness appears to be protracted, and its terms 

 somewhat evaded or extended. The egg, in other words, 

 develops into the mature form only after passing through an 

 extended development, and evolves the similitude of the 

 parent-form through certain intermediate stages of well- 

 marked kind. And so also with the well-known barnacles 

 which attach themselves to the sides of ships and to floating 

 timber. The young barnacle (see Fig. 22) appears as an 

 active little creature, possessing limbs adapted for swim- 



FIG. 32. Metamorphosis of swallow-tailed butterfly ; a, larva ; I, chrysalis ; c, 

 perfect insect or imago. 



ming, along with feelers, eyes, and other appendages. Ulti- 

 mately, the embryo-barnacle forms its shell, loses its limbs 

 and eyes, attaches itself by its feelers to some fixed object, 

 develops its flexible stalk, and passes the remainder of its 

 existence in a fixed and rooted condition. The development 

 in this latter case, although in due time producing the like- 

 ness of the parent, clearly leads to a state of life of much 

 lower character, and to a structure of humbler grade, com- 

 pared with the life and organisation of the young barnacle. 



