SECTION VIII. 155 



For the arrangement of thefe chambered 

 Shells, we muft have recourfe to the foffil 

 kingdom ; fince there are only two genera 

 of the fix, viz. the Litultes and Nautilus, 

 that are known recent or from fea. Con- 

 fequently the foflil kingdom alone helps 

 lis to arrange four .whole genera, and 

 many fpecies of the two other genera in 

 the fyftem of Shells, all which yet remain 

 undifcovered living or recent from fea. 



In my twenty- fifth lefture, on foffils, I 

 have treated this fubjefl: fuDy ; and hav^ 

 obferved how furprizing it is, that thefc' 

 genera, which are found foffil in fuch amaz- 

 ing abundance, all over the globe, and 

 befides are numerous families, have to this 

 hour efcaped the refearches of mankind, 

 to difcover them recent or livin^:. Befides 

 other arguments given, their being Pe- 

 lagian Shells, or Shells that inhabit the very 

 deepeft recefies of the fea, feems one prin- 

 cipal caufe ; as thofe deep reqeffes are not 

 fiibjecl to the agitations of the great tern- 



pefts 



y 



