Lucy discovers that skill which is forbidden to the very young: the awesome ability to get out of the crib by herself. This is, I think, one of the last strips in which Lucy interacts with her unseen father. Linus is showing up very soon, freeing Lucy for use in other capacities.
Lucy's eyes are still part-way between their evolution from circles with dots inside them to full parenthesis. Of all the major characters in Peanuts, only Lucy, Linus and Rerun have parenthesis around their eyes. This gives them subtly stronger powers of expression than the other characters, since we can always see the assumed corner of their eyes, instead of only when characters are looking in a direction other than they're facing (which produces eyes-as-apostrophes).
