Many laws regulate variation, some few of which can be dimly seen, and will hereafter be briefly discussed.

I will here only allude to what may be called correlated variation.

Important changes in the embryo or larva will probably entail changes in the mature animal.

In monstrosities, the correlations between quite distinct parts are very curious; and many instances are given in Isidore Geoffroy St.

Hilaire's great work on this subject.