Looks like unripe guavas to me.

The inside looks like gauva and the outside looks like Bael Fruit....but it does not appear to be either of those. You pose an excellent question......one, to which I have no answer.

Harry

I agree with Harry about the outside looking like bael fruit. I don't see the guava resemblance on the inside though.

I have never seen the inside of an unripe bael fruit. Bael flesh has a really nice smell when ripe but I am not sure if it smells like paint thinner while unripe. Do you have any more pics of the foliage?

My wife says it's calabash tree (aka morro) used for horchata.

Jeff

Jeff's wife has it!

Calabash.

Here is a link that might be useful: Calabash

Thanks so much for the ID Jeff. I read that the seeds are used to make horchata and the pulp is given to the animals. I don't know if this particular fruit was completely ripe but I split another that had dropped from the tree and the pulp was softer but still had an unpleasant smell. I was surprised I found as many varieties of ripe fruit as I did being that it was so early in the season. I wish that quinepas had been in season. They are difficult to find around here

Hi Karen,
Sounds like you had a great trip. I love finding tropical fruits I have never seen before. I love quenpas myself. Did they have mango in season? I sent an email to you a while back. Maybe it was when you were in Puerto Rico? Glad to see you on the forum. When and if you have the chance to email me please do.

Andrew