BARNACLES. 195 



next to impossible that any organised body inclosed in the 

 given area should escape. 



But there is more in them than merely this minute and 

 wide-spread ramification. They are, as we hate seen, 

 organs of touch ; so that the net has not only the mechani- 

 cal power of capture, common to an inanimate cast-net 

 which a human fisher uses, but is endowed with the most 

 exquisite sensibility in every part. The slightest contact 

 of an animalcule in the inclosed water with one of those 

 thousands of sensitive hairs communicates instantly an 

 impression to the sensorium, and a consciousness of the 

 fact to the Barnacle ; who is thus, without doubt, able 

 with the quickness of thought to close the fingers together 

 at that part, and thus secure the victim. 



To make use of the prey thus secured, the Barnacle is 

 furnished with a mouth, which can be protruded into a 

 sort of wart, and is provided with a distinct lip bearing 

 minute palpi, and three pairs of jaws, of which the outer 

 two are horny and toothed, while the innermost is soft 

 and fleshy. 



Fixed and immovable as the Barnacles are in their 

 adult and final stage, they have passed by metamorphosis 

 through conditions of life in which they were active, roving 

 little creatures, endowed with the power of swimming 

 freely in the wide sea. In this condition they present the 

 closest resemblance to familiar forms of Crustacea, as you 

 will perceive when yon examine some specimens of the 

 larvae that I am able to show you. 



I have in one of my tanks an individual of the fine and 

 large Barnacle, Balanus porcatus, which, for several days 

 past, has been at intervals throwing out from the orifice of 

 its shells dense clouds of atoms, which form compact 

 columns reaching from the animal to the surface of the 

 water. One of these cloudy columns, when examined with 

 a lens, is seen to be composed of thousands of dancing 

 creatures, resembling the Water-fleas that we lately ex- 



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