Help with mobi -> epub small leading text

Sorry but I don't know enough to do a search for this either here or in Google. I don't know what to call it.

When I convert a mobi to epub I get the following at the beginning of each chapter:

mobi:

Now is the time for all good men

epub:

Now is the time for all good men

The leading words are actually smaller than above, I can't clearly reproduce what I see.

I did try to search for "very small leading words" and variations thereof.

Thanks for any help.