BAKNACLES. 231 



included witliin two convex valves, like those of a 

 mussel or other bivalve shell, either united by a hinge 

 along the back, or rather soldered together there, so as 

 only to allow a slight opening and closing by the elas- 

 ticit}' of their substance. The fore part of the head is 

 now greatly enlarged, as are also the antenna?, which 

 project from the shell. The single eye is separated into 

 two. which are lar2:e and attached to the outer arms of 

 two bent processes which are placed within the body, 

 in the form of the letters U U • The legs are increased 

 by the addition of two pairs, and these are doubly 

 bent in a zig-zag form, and can be protruded from be- 

 tween the valves. 



It is a highly curious fact that the infant Barnacle 

 has thus passed through two distinct types of animal 

 life, the Cyclops and the Cypris. These are not one 

 type in different stages, as might be reasonably pre- 

 sumed. The young of Daphnia and of Cyclops are so 

 much alike, that it would be natural to presume the 

 young of Cypris to be of the same form ; in which 

 case, we should have in the young Barnacle merely the 

 first and second stages of Cypris. But it is not so. 

 Cypris does not pass through the Cyclops form at all ; 

 for, according to Jurine, the young when hatched have 

 the appearance of the perfect animal, though varying 

 a little in the shape of their shells. 



It is in this second form, which uaay be considered 

 the pupa of the Barnacle, that the animal quits its free 

 roving life, and becomes a fixture for the remainder of 

 its days. And this is a most wonderful process ; so 

 wonderful, that it would be utterly incredible, but that 

 the researches of Mr. Darwin have proved it incontest- 

 ably to be the means by which -the wisdom of God hag 



