FE ne RS et ee ee a eT se 
a 
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Natural History of the United States. 333 
lar application of them, are two distinct questions; and if the 
former be established, discussion becomes restricted to the latter, 
_ While perceiving that science has here derived views respect- 
Ing Branches, Classes, and the other subdivisions, which will 
contribute much to her progress, and also believing that inde- 
pendent types of structure (using this word in its most general 
sense) are the true basis for the subdivisions which are to be co- 
ordinated into system, or rather to be recognized in their natural 
coordinate and subordinate relations, we are still led to inquire— 
Whether the number of primal subdivisions is necessarily in 
all departments of life only those stated? whether the number 
of primal subdivisions between Order and Genus is in all cases 
but one, all others being subordinate to Order and Family? In 
what sense the idea of rank, made characteristic of the Orders, 
Branches (the Vertebrate, Articulate, Molluscan and Radiate,) hav- 
Mg a distinct ordinal relation among themselves; so the Classes 
Under these branches (as Insects, Crustacea and Worms in the 
id aaa d, even in divisions as high as Orders, and 
tether it is not for this reason,.in part, that the system is not so 
inedoth in which the criteria 
1des of speci 
less easily devided off into grades than if distributed between 
Wide extremes, and especially if, at the same time few m num- 
Vhether, when we leave the grand level ne eed 
4°") and so proving that some actual difference exists among 
the multitudes even ones not to be detected by any known 
jthods hether one of the grand subdivisions of a Class, 
. an Order, ete., does not often stand apart, as an expression o 
NeW or intruded idea, not involved in either of the other grand 
