The skull in this low group of placental Mammals ( Eutheria ) is of great interest, and, knowing this, I have lost no opportunity, for many years past, of procuring specimens of all sorts, and of all ages and stages. The native kinds, namely, the Hedgehog, Mole, and Shrew, form perhaps, on the whole, as instructive a group as could be found anywhere; they are related, and yet distantly, and the Mole comes in well between the generalised Hedgehog and the very specialised Shrew. I have been able to follow the Hedgehog and the Mole through a large series of stages, and the Shrew in four—so that these native kinds will now have the history of their skull fairly written out. But the exotic kinds of Insectivora do not yield a jot, in interest, to those familiar to us here; these I have been less fortunate in procuring. Yet I think that I can now offer to the Society a sufficiently detailed account to serve, by the help of the more exhaustive account of the skull in the native kinds, to give a clear idea of the morphology of the skull in the more important Families of this most instructive Order.