afford some slight protection, this having given the basis for the subsequent acquisition of the most perfect resemblance.

3. On The Nature Of The Affinities Connecting Organic Beings

As the modified descendants of dominant species, belonging to the larger genera, tend to inherit the advantages which made the groups to which they belong large and their parents dominant, they are almost sure to spread widely, and to seize on more and more places in the economy of nature. The larger and more dominant groups within each class thus tend to go on increasing in size, and they consequently supplant many smaller and feebler groups.

Thus, we can account for the fact that all organisms, recent and extinct, are included under a few great orders and under still