LIMPETS. 233 



lu tlie rock-adhering Limpet, the senses of feeling and 

 taste^ and perhaps hearing, are alone developed; another 

 species moves readily from place to place, though sightless, 

 as the Pinna ; a third apparently possesses every sense, with 

 higher instincts and facilities for enjoyment. Between these 

 an unbroken link of connection undoubtedly exists, and 

 therefore, when the observer arrives at certain gaps in the 

 chain of nature, or rather at certain divisions in the gene- 

 ral classilication between which it is difficult to establish 

 an affinity, the deficiency can only be ascribed to the ab- 

 sence of forms which have eluded his researches. 



Hence it is that the naturalist seeks earnestly, by the aid 

 of certain symbols or characters, to bring the objects by 

 which he is surrounded within the bounds of his mental 

 range : with this view he forms a series of artificial divisions, 

 such as classes, orders, and families, with still smaller sub- 

 divisions ; and while thus employed, he rejoices in the disco- 

 very of new forms, that tend to diminish the gaps which still 

 remain open, in a system which he knows to be all perfect. 



Yery beautiful are such fillings up, and happy is the 

 conchologist when permitted to add even one to those which 

 have already rewarded the researches of his predecessors 

 in the paths of natural history. 



