The fossil Myriapods, then, are arranged as follows:—
| Order | I. | Protosyngnatha. |
| Order | II. | Chilopoda. |
| Order | III. | Archipolypoda. |
| Order | IV. | Chilognatha (or Diplopoda). |
The following table will show the species that have been discovered in the different strata:—
| Devonian, or Old Red Sandstone |  | 2 species of Archipolypoda | ||
| Carboniferous |  | 01 species Protosyngnatha 31 species Archipolypoda | ||
| Permian (Rothliegendes of Germany), 4 specimens belonging to the Julidae or Archipolypoda. | ||||
| Cretaceous | 01 species | | Archipolypoda or Chilognatha | |
| Oligocene |  | 17 species | Chilopoda | |
| 23 species | | Diplopoda (Chilognatha) | ||
| Miocene, | 01 species | | Diplopoda (Chilognatha) | |
I will now give a short account of the different Orders, and the fossil forms which are included in them.
Order I. Protosyngnatha.
This Order is represented by a single fossil (Fig. 45), discovered in the coal at Mazon Creek, Illinois, America, by Meek and Worth. It differs greatly from any of those in existence at the present day. The body is cylindrical, and composed of ten segments. The cephalic appendages (that is, the antennae and mouth parts) are inserted into a single unsegmented cephalic mass (the head). Each segment behind the head bears a single dorsal and ventral plate of equal breadth and length. The limbs are placed in these plates with a wide space between the base of each leg and that of the opposite one of the pair. Along the back, bundles of bristles are arranged in longitudinal rows.
Order II. Chilopoda.
The fossil forms of this Order resemble those of the Chilopoda of the present day. The oldest of them are found in amber. The following families have been found:—
Lithobiidae. Several species have been found in amber.