THE ROCK-BARNACLE 



73 



ing figure. Remark the horns which project from the 

 sides of the head-region, the eye, apparently single, but 

 really consisting of two eyes set close together, and the 

 jointed limbs, the two hinder being forked. Even a 

 beginner in zoology, if he should happen to know his 

 crayfish, will recognise this as a crustacean ; the forked 

 and jointed limbs are proof enough of that. A zoologist 

 of somewhat wider knowledge will say at once that it is 



FIG. 17. Nauplius of rock-barnacle in side-view, magnified. 



a crustacean in its first or Nauplius stage. 1 Zoologists 

 who happen to have attended to the Crustacea will go 

 further, and pronounce that this is the nauplius of a rock- 

 barnacle. It is an early locomotive larva, destined, if 

 lucky enough to escape the thousand risks that await it, 

 to settle down on a tidal shore and change into a rock- 

 barnacle, such as any one of the multitude that we glanced 

 at this morning. 



1 Nauplius is an old name given to a Cyclops-larva by O. F. Miiller, 

 and now retained to denote, not a particular sort of animal, but a stage of 

 crustacean development. 



