BALANUS. 



157 



limpet was covered with acorn-sliells ; but one 

 or two were removed, in order to show the nature 

 of the substance on which they rested. Their 

 scientific name is Balanus halanoides, and they 

 belong to a class of molluscs that are called 

 Cirrhopoda, on account of the cirrhi, or ciliated 

 arms, which form their chief characteristic. 



The first acquaintance that is usually made 

 with these animals is seldom of an agreeable 

 nature, and generally takes place after the fol- 

 lowing manner: — An inexperienced but earnest 

 observer is picking his way among the rocks and 

 stones at low water, his eyes being more engaged 

 in searching for curiosities than in looking after 

 his own feet. Suddenly, he puts his foot on a 

 sloping rock, rendered slippery as ice by the slimy 

 algae that cover it, or is inadvertently caught in a 

 rocky pitfall, whose orifice was concealed by the 

 heavy masses of wrack or tangle that are flung 

 over it by the tide, and at the bottom of which 

 is a pool of water just deep enough to wet his 

 feet, and to irrigate his body by spirting up along 

 the sides of the cavity. In either case he catches 

 frantically at the nearest piece of rock, and finds 

 his fingers cut in several places by the sharp 

 edges of the acorn-shells that have there affixed 

 themselves, and present as uncomfortable a hold 



