BARNACLES. 197 



double from the basal joint outwards, while the first 

 pair are simple. In the fore part of the body a large eye 

 is placed, deep-seated, which is of a roundish form, and 

 is intensely black both by reflected and transmitted light. 

 On the summit of the forehead are placed a pair of thick 

 flexible horn-like organs, which are abruptly bent in the 

 middle, and which I believe represent the first pair of 

 antennae. This then is the first stage of the Barnacle, — 

 the form under which it appears when it is hatched from 

 the egg. 



YOUNG OF BARNACLE. 



Among the multitudes which have been evolved during 

 these last few days, and which are now swimming at large 

 in the tank, we may be able to detect some that have 

 passed through their first stage, and, having moulted their 

 skin, have attained a more advanced form. Here is one, 

 which by its superior size seems to have made some pro- 

 gress towards maturity. 



