I am sorry to say that I cannot answer your question; nor do I believe that you could find it anywhere even approximately answered.

It is very difficult or impossible to define what is meant by a large variation.

Such graduate into monstrosities or generally injurious variations.

I do not myself believe that these are often or ever taken advantage of under nature.

It is a common occurrence that abrupt and considerable variations are transmitted in an unaltered state, or not at all transmitted, to the offspring, or to some of them.
So it is with tailless or hornless animals, and with sudden and great changes of colour in flowers.