Newbie: Composition by Association - Pagination Class general question.

Hello, I have a Animals DAO class that I'd like to apply a pagination class to it. Between this two classes, there will be a composition relation (more precisely, an association one). My question is: Is a Pagination that "has a" Animal. OR Is a Animal that "has a" pagination? Should we create on Class Pagination a property named $_animal OR, should we create on class Animal a property named $_pagination? I'm inclined to accept the second one, since, if I put the property $_animal on my classe Pagination, I will end up, on the Pagination Class, with so many properties as pagination objects... :s Any help please? Márcio