with other representative species of the same genus whose limits are
confined."

It may be noted that in large genera the species often have small ranges
("Origin," Edition VI., page 45), and large genera are more commonly
wide-ranging than the reverse.) To give an example, the genus Felis
is found in every country except Australia, and the individual species
generally range over thousands of miles in their respective countries;
on the other hand, no genus of monkey ranges over so large a part of the
world, and the individual species in their respective countries seldom
range over wide spaces. I suspect (but am not sure) that in the genus
Mus (the most mundane genus of all mammifers) the individual species
have not wide ranges, which is opposed to my query.

I fancy, from a paper by Don, that some genera of grasses (i.e. Juncus
or Juncaceae) are widely diffused over the world, and certainly many of
their species have very wide ranges--in short, it seems that my question
is whether there is any relation between the ranges of genera and of
individual species, without any relation to the size of the genera. It
is evident a genus might be widely diffused in two ways: 1st, by many
different species, each with restricted ranges; and 2nd, by many or
few species with wide ranges. Any light which you could throw on this I
should be very much obliged for. Thank you most kindly, also, for your
offer in a former letter to consider any other points; and at some
future day I shall be most grateful for a little assistance, but I will
not be unmerciful.

Swainson has remarked (and Westwood contradicted) that typical genera
have wide ranges: Waterhouse (without knowing these previous
remarkers) made to me the same observation: I feel a laudable doubt and
disinclination to believe any statement of Swainson; but now Waterhouse
remarks it, I am curious on the point. There is, however, so much vague
in the meaning of "typical forms," and no little ambiguity in the mere
assertion of "wide ranges" (for zoologists seldom go into strict and
disagreeable arithmetic, like you botanists so wisely do) that I feel
very doubtful, though some considerations tempt me to believe in this
remark. Here again, if you can throw any light, I shall be much obliged.
After your kind remarks I will not apologise for boring you with my
vague queries and remarks.

LETTER 315. TO J.D. HOOKER. Down, December 25th [1844]. Happy Christmas
to you.

(315/1. The f