256 BARNACLES. 



that two of them had thrown off their exuviae, and, 

 wonderful to say, were firmly adhering to the bottom of 

 the vessel, and changed to young barnacles. In this stage 

 the sutures between the valves of the shell and of the 

 operculum were visible, and the movements of the arms 

 of the animal within, although these last were not com- 

 pletely developed : the eyes also were still perceptible, 

 although the principal part of the colouring-matter ap- 

 peared to have been thrown off with the exuviae. On the 

 roth another individual was seen in the act of throwing 

 off its shell, and attaching itself as the others to the bot- 

 tom of the glass. It only remains to add, that as the 

 secretion of the calcareous matter goes on in the compart- 

 ments destined for the valves of the shelly covering, the 

 eyes gradually disappear, from the increasing opacity 

 thence produced, and the visual ray is extinguished for 

 the remainder of the animal's life ; the arms at the same 

 time acquire their usual ciliated appearance. Thus, then, 

 an animal originally natatory and locomotive, and provided 

 with a distinct organ of sight, becomes permanently and 

 immovably fixed, and its optic apparatus obliterated ; and 

 furnishes not only a new and important physiological fact, 

 but is the only instance in nature of so extraordinary a 

 metamorphosis. 



We have been thus led to dilate upon barnacles in con- 

 nection with Shakespeare's allusion to them, at somewhat 

 greater length than we should otherwise have done, on 

 account of the interest which attaches to the old story, 



