106 OUn CAHCINOLOQICAL FRIENDS. 



our coast, thu two commoner hoiiig Lcpas anad/irn, 

 in which the stalks grow to a length of from four 

 to six inches, and Lepas fascicularis, in 

 which, as the name indicates, a consid- 

 erable number of individuals are closoly 

 bunched together or fasciculated. The 

 former Bpocies, found on the bottoms of 

 lepabpascic- ships, is probably not indigenous to tliu 

 region. It is an erroneous notion, which 

 is shared by many, that the barnacles in any way 

 injure the holds of vessels to which they may bo 

 attached. They merely impede navigation througli 

 the resistance which their enormous numbers oftbr 

 to the water, and hence the necessity of keeping 

 vessels clear of their colonies. An effective method 

 of removal, frequently practised by sailing-masters, 

 is to drive a barnacled vessel into fresh water, where 

 the animals soon die and drop off. 



Belonging to the same order of animals as the bar- 

 nacles proper are the acorn-shells, those crater-like 

 eminences that are found so abun- 

 dantly encrusting rocks at about 

 high-water mark, and scarcely loss 

 abundantly on the surfaces of shells, 

 ^m^ides). drift-wood, etc. They have the same 

 general structure as the goose bar- 

 nacle, but are devoid of the stalk or peduncle, and 

 are hence known as 'sessile' barnacles. Where 

 attached to a rock they leave a peculiar circular 

 stamp of lime, which is not infrequently taken for 

 a coral impression. 

 The shell of the acorn is usually conical in out- 



