But there was one remarkable exception to this rule, for the young of the short-faced tumbler differed from the young of the wild rock-pigeon, and of the other breeds, in almost exactly the same proportions as in the adult stage.

These facts are explained by the above two principles.

Fanciers select their dogs, horses, pigeons, etc.

, for breeding, when nearly grown up.

They are indifferent whether the desired qualities are acquired earlier or later in life, if the full-grown animal possesses them.