EXUVIAE OF THE ACORN-SHELLS. 147 



be, in the wide range of Nature's lower scale of life, 

 prettier sights to gladden the eye of the student than- 

 that above described, but if so, I must confess my 

 inability to indicate where such are to be found. 

 The fishing apparatus here mentioned consists of a 

 number of slender cirri, thickly coated with micro- 

 scopic filaments (cilia), and is, at certain periods, 

 thrown off complete and entire by the process of 

 exuviation, just as we have seen it occur in the 

 higher Crustacea. 



Would you, my young friend, like to procure an 

 exuvium of the Barnacle for examination ? Yes. 

 Then follow the directions I am now about to give, 

 and your wish will be speedily gratified. 



Presuming that your tank already contains a 

 number of Barnacles attached to various objects, and 

 that such have been in the same vessel for some 

 weeks ; syringe the water for a few minutes, and you 

 will find floating about, or rising to the surface, many 

 specimens of the desired object. They will, in all 

 probability, be visible to the naked eye. To attempt 

 to lift one out of the water, however, by means of 

 your finger and thumb would be utterly useless. 

 Such a procedure, even were it successful, would 

 inevitably mar the delicate beauty of this ' inessen- 

 tial' object, which, spirit like, casts no shadow upon 

 weed or water. The best plan is to insert a tube of 

 glass into the aquarium, in such a way that the 

 exuvium may ascend the interior. Then place 



