Spanish Limes (Melicoccus bijugatusaka Quenepa, Genips, Wayas, Mamoncillos) are, despite their name, not a citrus fruit. Though they look a bit like small limes from the outside, they actually in the same family as lychees, longans and rambutans. Inside their thin, taut green skin is a large seed (or, rarely two seeds) tightly surrounded by pink/yellow, translucent, creamy, sweet-tart pulp.
Spanish limes range in weight from .3 to .8 ounces.