Marsh states that he had fully satisfied himself that Archaeopteryx belonged to the Odontornithes, which he thought it advisable for the present to regard as a subclass, separated into three orders - Odontolcae, Odontotormae and Saururae - all well marked, but evidently not of equal rank, the last being clearly much more widely distinguished from the first two than they are from one another.
Instead of recognizing, as before, a subclass in the Ratitae of Merrem, Nitzsch now reduced them to the rank of an order under the name " Platysternae," placing them between the " Gallinaceae " and " Grallae," though admitting that in their pterylosis they differ from all other birds, in ways that he is at great pains to describe, in each of the four genera examined by him - Struthio, Rhea, Dromaeus and Casuarius.
Crystals of blende belong to that subclass of the cubic system in which there are six planes of symmetry parallel to the faces of the rhombic dodecahedron and none parallel to the cubic faces; in other words, the crystals are cubic with inclined hemihedrism, and have no centre of symmetry.
The second subclass, Gamopetalae, includes 9 series and culminates in those which show the most elaborate type of flower, the series Aggregatae, the chief representative of which is the great and wide-spread order Compositae.
Haeckel established the subclass Saururae, containing solely Archaeopteryx, in opposition to the Ornithurae, comprising all the other birds.