Can a crested guinea pig breed with abyssinian?

Ok, a crested guinea pig and, I'm guessing you are referring to an abyssian guinea pig (not a cat) CAN breed. They are NOT two different species of animals. They are different BREEDS. Both are guinea pigs, so they can breed. Think of a lab (dog) and a dachshund (dog)........they, too, are different BREEDS, but the same SPECIES (dog)......so, they can also breed.