At times you can buy limes that are labeled ‘Mexican limes’, or just ‘limes’ but listed as coming from ‘Mexico’.
These Mexican limes are smaller and sweeter with an unique fragrance. The word for ‘lime’ in Spanish is ‘lima‘ but in Mexico these limes are called ‘limones’ (lemons) or ‘limones verdes’ (green lemons), so really they are not limes at all, but lemons!
If you are planning of using a lot of limes it is worth getting hold of a Mexican ‘lime’ squeezer. Note that the regular limes you buy at the grocery store are usually too big for this squeezer but of course Mexican limes fit just perfectly, and it also made quick work of the 20 or so tiny ‘Key’ limes that I needed to make Key Lime Pie.
Once I made ceviche with regular limes and result was so sour it was barely edible. In a panic I phoned a friend and professional cook and she suggested adding some orange juice to the marinade which improved it immensely. Still, it would have been better with real Mexican ‘limes’!