CONSTANCY.
Constancy may be symbolised by the phoenix which, knowing that by nature it must be resuscitated, has the constancy to endure the burning flames which consume it, and then it rises anew.
INCONSTANCY.
The swallow may serve for Inconstancy, for it is always in movement, since it cannot endure the smallest discomfort.
CONTINENCE.
The camel is the most lustful animal there is, and will follow the female for a thousand miles. But if you keep it constantly with its mother or sister it will leave them alone, so temperate is its nature.
Taken from The Notebooks of Leonardo da Vinci edited by Jean Paul Richter, 1880.