208 ON SYSTEMATIC ZOOLOGY. 
MOLLUSCA 
Branchiopoda OF Reptilia 
ACRITA 
Intestina 
VERTEBRATA 
Mammalia 9 
ANNELIDA 
Be 
RADIATA ANNULOSA 
CIRRIPE 4° 
(262.) This diagram fully explains our author’s 
meaning in the foregoing passage, when he supposes 
that ‘‘ opposite points of a circle may possibly meet each 
other,” and consequently unite. Now, if this, in the 
sense here taken, and in the instances here stated, were 
true, the inevitable consequence would be, that the 
Acrita, the Mollusca, and the Vertebrata, would form 
one great circle of their own, by the union of the intes- 
tinal Acrita with the Annelida, while the circle of Ver- 
tebrata would be divisible in the first instance into two, 
by Ornithorhynchus uniting the reptiles with the qua- 
drupeds (Mammalia). It is somewhat surprising, 
therefore, that our acute author did not perceive the 
inevitable consequences which would result to his own 
theory, by admitting the possibility of such a principle 
of affinity: for either it would, if correct, entirely 
overturn his own theory on the animal kingdom being 
first resolvable into five large and five smaller circles ; 
or it would show that circles of affinity could be ex- 
pressed in more ways than one, — in other words, that 
there was more than one natural system. The truth, 
however, appears to be, that some of the foregoing 
resemblances are relations of affinity, while others are 
