142 NEREIS. 



CHAPTER V. 



NEREIS, SPIO, AND CONGENERA. 



COULD the Systcma Natures be perfected, it is not improbable that, 

 excepting by interruption from tribes now extinct, the transition to suc- 

 cessive genera would be very gradually accomplished ; if not by insensible 

 degrees, one might venture to predict that the last of one genus, and the 

 first of another, would appear not far asunder ; that the distinctions pre- 

 sented would be but inconsiderable, farther than in the features peculiar 

 to each denoting their separation. 



I know that some distinguished philosophers have expressed a dif- 

 ferent opinion, thinking each genus so distinct and independent of itself, 

 as to be void of every bond of connection ; that it has been so since the 

 origin of things, and will so remain. 



Whether there be actually a connecting chain or not, it belongs to 

 each observer diligently to record what he has seen, leaving it to some 

 scientific systematist to arrange and combine all the knowledge which 

 may be derived from the labour of others besides his own. 



In this way the precise state of information would be obtained, 

 so that the purposes of creation might be conjectured, and whether cer- 

 tain genera were allied or estranged. 



There is no single territory, even the most extensive on the surface 

 of the globe, from which more than a partial view, commonly one most 

 limited, of some branch or other of animated nature, can be derived, 



