BARNACLES. 195 



delicacy that it is 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 have seen, 

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

 nical 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 you 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 i^orcatus, 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 ex- 

 amined with a lens, is seen to be composed of thousands 

 of dancing creatures, resembling the Water-fleas that 



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