On the present state of Zoology. 19 
animals to some general principles, and who are equally satisfied with 
him, that they have attained to a knowledge of these principles in the 
main. We mention this, in order that it may not excite his surprise, 
if those who attach themselves to no particular party should consider 
one set of principles as much entitled to their regard as the other, and 
should withhold from both, at present, their unlimited confidence. We 
should be sorry to be thought to offer any opposition to those which 
Mr Swainson advocates. We simply wish to see them better substan- 
tiated, than, in our opinion, and, we believe we might add, in that of 
a large proportion of the naturalists of this country, they are at pre- 
sent. With respect, in particular, to the law of circular affinities, it 
is undoubtedly true, that many groups, which have all the appearance 
of being natural, evince a decided tendency to such an arrangement, 
and, reasoning from analogy, it seems highly probable that this prin- 
ciple may extend throughout nature ; but let us investigate the affini- 
ties of animals more closely, of those especially, which, being low down 
in the scale of organization, have as yet obtained but slender attention 
from naturalists, before we consider this point as resting upon anything 
like " mathematical certainty." In fact, the supposed proof of this 
principle is involved in the fate of two others : that which assigns a 
definite number of subordinate divisions to each group, and that upon 
which depend those symbolical representations of which we have be- 
fore spoken. The whole theory may, in short, be said to rest upon 
relations of analogy conforming to an apparent law, these relations 
themselves, however obvious in certain cases, being, when remote, so 
obscure as to be hardly palpable, when very near, so striking, that, ac- 
cording to Mr Swainson's own shewing, there is danger of confound- 
ing them with relations of affinity.* We would not willingly assert, 
that Mr Swainson has suffered his own judgment to be warped by an 
active imagination. But certainly we must say, that some of the re- 
lations which he has pointed out are such as we conceive few besides 
school, either in his Treatise on the " Rise and Progress of Zoology," (Prelim. 
Disc, part 1.) or in a subsequent Treatise on the " Rise and Progress of Syste- 
matic Zoology ;" (Classific. of An. part 2.) We are inclined to think that the 
Germans are equally strangers to the school founded in England by Mr Macleay, 
since we find M. Agassiz adverting to the " philosophic naturalists" of Germany, 
as those who alone have sought after general principles. See Notices of Com- 
mun. to the Brit. Assoc. 1835, p. 67. 
* Speaking of analogical relations, Mr Swainson observes ; " In proportion 
as groups approximate, other dissimilarities of course become less, so that when 
we descend to genera which follow or come very close to each other, it is impos- 
sible to decide, at first sight, whether the relationship be one of analogy or of affi- 
nity." Prelim. Disc. &c. p. 215. 
