Maybe there's a card inside the box.
3 seconds sound clip from the Murders in the Rue Morgue (1932) movie soundboard.
You can hear this line at 00:30:28.392 in the Blu-ray version of the movie.
Quote context
[...]
- For pity's sake, what is it? What are you so excited about?
- See what just came. A new bonnet.
- Oh, now, who could have sent it?
- Oh, where would Pierre get money enough to get a present like that?
- Maybe there's a card inside the box.
- You know, I told you. The funny old man at the sideshow who owns the ape.
- Shall I wear it to the picnic?
- Why not?
- I wonder how he found out where we lived.
- He wanted to know. But Pierre wouldn't let me tell him.
[...]