The textbook uses the following examples:
“All animals are human” — false.
“No animal is human” — also false, since some animals are human.
Two universal propositions can thus both be false; they are not contradictories.
Likewise:
“Some animals are human” — true.
“Some animals are not human” — also true.
Two particular propositions can thus both be true.
Consequently both quantity and quality must be reversed: universal affirmative pairs with particular negative, and universal negative with particular affirmative.