1900J MICROSCOPICAL JOURNAL. 345 



ble of separating. These are Barnacles, class Crustacea, 

 division Cirripedia (from cirrus, a curl, and pes, a foot), 

 order Balanidae (from balanus, an acorn). Fixed and im- 

 movable as barnacles are in their adult stage, they have 

 passed by meta-morphosis through conditions of life in 

 which they were roving little creatures, swimming free- 

 ly in the sea. It is in these conditions that they present 

 the closest resemblance to familiar forms of crustacsee. 

 Tiie Nauplius stage of the barnacle has a broad carapace, 

 a single eye, two pairs of anteunsB, three pairs of jointed, 

 branched and well-bristled legs, and a forked tail. The 

 skin is cast twice, considerable change of figure resulting. 

 At the third moult it assumes the cypris stage, and is en- 

 closed in a bivalve shell, with the front of the head and 

 the anteunfe greatly developed, the single eye having be- 

 come two. In this stage the little creature searches for 

 a suitable spot for a permanent reiidence. The two an- 

 tennsB which project from the shell pour out a glutinous 

 gam which hardens in water and fixes them. Another 

 moult takes place, the bivalve shell is thrown off, the 

 carapace is composed of several pieces, whilst ilie legs are 

 modified in o cirri and made to execute their grasping 

 movement. Nothing can be more efi'eotive or beautiful 

 than the manner in which the cirrus obtains its prey. The 

 cirri are alternately thrown out and retracted with great 

 rapidity, and when fully expanded the plumose and flex- 

 ible stems form an exquisitely beautiful apparatus, admi- 

 rably adapted to entangle any nutritious atoms or minute 

 living creatures that may happen to be present in the cir- 

 cumscribed space over which this singular casting-net is 

 thrown, and drag them down to the vicinity of the mouth. 

 This action may be easily seen if a small portion of rock 

 be chipped off, having barnacles on it, and placed in a 

 glass with sea-water. A hand-glass will show the beau- 

 tiful little hand with twenty-four long fingers, the net 

 with which this fisher takes his prey, busily at work. Care 



