What were the earliest land animals?
The first land-dwelling animals were segmented and probably represented the ancestors of the millipedes you encounter today and reached spectacular sizes (up to 2m in length). The exoskeleton inherited from aquatic ancestors needed only minor modification, but the external gills were unsuitable and in its place a network of breathing tubes (tracheae) evolved. Each tube has an exterior opening on the side of the exoskeleton, and the network of tracheae provides each cell with a supply of oxygen.Millipedes
Rusty millipede(Trigoniulus corallinus)