The feature found in eukaryotic cells but not prokaryotic cells is a nucleus.

Here's why:

* Eukaryotic cells have a true nucleus, which is a membrane-bound organelle that contains the cell's DNA.

* Prokaryotic cells lack a nucleus. Their DNA is located in a region called the nucleoid, which is not enclosed by a membrane.

Let me know if you'd like to know more about eukaryotic or prokaryotic cells!