In these four subfamilies the concentric shells are all simple (not spongy) fenestrated spheres or endospherical polyhedra.
The seven subfamilies of the Prunoidea can be arranged in two sections according to the presence or absence of medullary shells.
The last three subfamilies have arisen probably from the first triradial subfamily, by a secondary increase in the number of rays.
The two subfamilies of Cœlodendrida therefore exactly correspond to the two subfamilies of the following family, the Cœlographida.
The family has two branches, or subfamilies as the books call them.
The family is divided into two subfamilies, the Psychodin and the Phlebotomin.
He includes these subfamilies, therefore, in the Family Parulidae.
They belong in two subfamilies, the Botaurinæ and Ardeinæ, respectively.
Within this larger grouping a number of subfamilies have been identified.
Two families (or subfamilies) of rat-like animals, Octodontid and Echimyid, are also divided by the Atlantic.