HISTORY OF BALANUS. 131 



brings home more or less of those invisible atoms of organic 

 matter upon which it feeds. It is in no idle play, therefore, that 

 the Balani are engaged while they thus sweep the water with 

 their feathery plumes : on the contrary, they are doing battle 

 for very life ; and, like many more important people above 

 water, they have to fight hard, or go hungry. 



The history of the inmate of the acorn-shell is one of the 

 wonders of marine natural history. In the first stage of its 

 existence the Balanus is a totally different being from what it 

 becomes in after life. Instead of being immovably fixed to one 

 spot at the sea-bottom, it roams the waters in perfect freedom, 

 impelled by the action of six pairs of swimming legs, which 

 keep stroke like so many oars, and send it along by a succession 

 of bounds, much after the fashion of the water-flea. At this 

 stage the young Balanus is also provided with eyes, and a large 

 pair of prehensile antenna?, which serve the little rover as a 

 means of attachment to submerged bodies, when, at any time, it 

 wishes to rest for a while from its more active exertions. All 

 through the spring and summer months, myriads of these juve- 

 nile Balani may be found disporting themselves in the water, 

 making the most of their temporary powers of locomotion. In 

 due time, however, the young Balanus selects a permanent 

 resting-place, and driving at it head foremost, sticks fast, at first 

 merely by the antennas, but, before long, a sort of cement, which 

 pours out from those organs, securely glues the animal to its 

 home, and it becomes a fixture for life. The eyes and the 

 antenna?, now no longer needed, are cast aside, the feathery arms 

 receive their full development, the shelly covering is gradually 

 secreted, and the inmate of the acorn-shell attains his majority. 



In selecting specimens of the Balani for the Aquarium, they 

 should always be taken from situations in which they are never 

 left wholly uncovered by the retiring tide. On many parts of the 

 coast they cover the rocks by myriads far up towards the high- 

 tide level, and are consequently left bare by the sea, and exposed 

 to the air and burning sunshine for several hours daily. This it 

 appears they bear unharmed; but if a cluster which has been 

 thus exposed be placed in the Aquarium, and constantly.immersed 

 in water, they speedily languish and die ; nor will a daily re- 

 moval from the water for a few hours suffice to keep them long 

 in health and activity. On the other hand, specimens taken from 



