Plexus: a knot: applied to a knot-like mass of nerves, or tracheae.
In Porcellio, air-tubes (tracheae) may be present (see below).
This is the cord of tracheae communicating between one breathing-hole and another.
Tracheae opening by a pair of stigmata situated above and behind the base of the 4th or 5th or 6th pair of appendages.
A great point of interest therefore exists in the knowledge of the structure and embryology of tracheae in the different groups.
Tracheae are abundant just in proportion as blood-vessels become suppressed.
Tracheae are developed which are dendriform and with spiral thickening of their lining.
I think the part about the relation of the wings and spiracles and tracheae might have been made a little clearer.
Besides the tracheae and tracheids already noted are such cells as "wood fiber," "fibrous cells," and "parenchyma."
In Scutigera the tracheae differ both in structure and position from those of all other Chilopoda.