ANALOGY AND AFFINITY ILLUSTRATED. aa 
have required an almost infinite degree of design before 
they could have been made exactly to harmonise with 
each other. When, therefore, two such parallel series 
can be shown, in nature, to have each their general 
change of form gradual, or, in other words, their rela- 
tions of affinity uninterrupted by any thing known — 
when, moreover, the corresponding points in these two 
series agree in some one or two remarkable circum- 
stances, there is every probability of our arrangement 
being correct. It is quite inconceivable that the utmost 
human ingenuity could make these two kinds of re- 
lation tally with each other, had they not been so 
designed in the creation. Relations of analogy consist 
in a correspondence between certain insulated parts, or 
properties, of the organisation of two animals which 
_ differ in their general structure. These relations, how- 
ever, seem to have been confounded, by Lamarck, and, 
indeed, all zoologists, with those upon which orders, 
sections, families, and other subdivisions, immediately 
depend.* 
(285.) To illustrate by an example the above de- 
finition, we will take two groups of birds, whose 
relations are unquestionable. The first shall be the 
primary orders of the class; the second, the primary 
tribes of the perching order. By placing these in “ pa- 
rallel series,” it will be found that the corresponding 
points of each agree in some one or two remarkable pe- 
culiarities of structure or of habits. 
Orders of Berds. Tribes of Perchers. 
1. Typicat Grour. Insessores. . . Conirostres. 
2. Sus-ryrican Group. MRaptores. . . Dentirostres. 
Natatores. . . Fissirostres. 
3. ABERRANT Group. Grallatores . . Tenuirostres. 
Rasores . . . Scansores. 
Here we have two series of natural groups arranged 
parallel to each other, but of different ranks. The first 
* Hor. Ent. p. 363 
Q 4 
