PRINCIPLES OF SCIENTIFIC ARRANGEMENT. 139 
are, however, bound by the common affinity of being 
all beetles. 
It is, nevertheless, often difficult to determine between 
the relationships of affinity and analogy, for groups even 
in close contiguity may also possess both. Thus, the 
normal Ichneumones have their analogues in the Ichneu- 
mones aclsciti, if the comparison be restricted to them¬ 
selves, but these revert into the relationship of affinity 
when a comparison is instituted between them and the 
adjacent groups on the one side of the Tentlire dines, or 
on the other of the Aculeata, with which, when a re¬ 
lationship presents itself, it is merely one of analogy. 
So, also, within the pentamerous Coleoptera we have 
a relationship of analogy between the Staphylinidce and 
the Histerulce, but it becomes one of affinity when it 
unites them within this section of the class. 
Innumerable other instances might be given readily, 
but these will suffice to convey a notion of the relative 
meanings of the terms, e relation of affinity 5 and ‘ relation 
of analogy/ which is all here aimed at. 
The problem naturalists have to solve is, “ What is 
the natural system ? 55 We can clearly see that the sys¬ 
tems adopted are not Nature 5 s, that they are essentially 
imperfect, and that the science, even with all the force 
of the intelligence that has been applied to it, is far from 
having attained perfection. It still aw r aits the master 
mind that shall cope with its difficulties, determine its 
intricacies, and, threading the labyrinth, guide his en¬ 
thusiastic disciples into the adytum of the temple. 
The subjects here brought under view admit of very 
considerable development, and of strictly didactic and 
methodical treatment. It has been my object only to 
gossip upon them, that I might stimulate curiosity to 
