These five genera have also much in common, though less than when grouped in subfamilies; and they form a family distinct from that containing the three genera still further to the right hand, which diverged at an earlier period.

And all these genera, descended from (A), form an order distinct from the genera descended from (I).

So that we here have many species descended from a single progenitor grouped into genera; and the genera into subfamilies, families and orders, all under one great class.