After a longer or shorter period it enters the alimentary canal of its proper host with drinking-water, or it bores through the skin and reaches the bloodvessels, and is so conveyed through the body, in which it becomes sexually mature.
This primitive condition occurs only in the Odontornithes, Ratitae and Tinami; in all others this notch becomes converted into a foramen ischiadicum, through which pass the big stems of the ischiadic nerves and most of the bloodvessels of the hind-limb.
There is a spacious cavity surrounding the gut and containing also bloodvessels, and to some extent the generative organs.
The longitudinal bloodvessels do the same.
Innocent tumours are usually sharply defined from the surrounding tissues, and show no tendency to spread into them or to pass by means of lymphatics and bloodvessels to neighbouring parts (fig.
Thoroughly rubbed into the skin alcohol dilates the bloodvessels and produces a mild counter-irritant effect.