Talking Pencil and a Dog that Could Swim Underwater

[captchris18]

When I was in grade school (around 8th grade, which would have been in 1978), I used to read and re-read two books in our library. One was about a magic pencil that a child owned. The pencil would talk to the child by writing things. The second was about a group of dogs, one of which learned to swim underwater.

I would love to find these books for my daughter, but I have failed to find them.

Does anyone know the name of the books or where I can find them?