Melons belong to the Cucurbit family, which includes cucumbers, pumpkins, gourds and squash. There are two categories of melons - watermelons and muskmelons. Watermelons range in size and shape from miniature balls to 20- to 30-pound oblong melons, with or without seeds. Muskmelons contain a central cavity filled with seeds. There are three basic skin types - ridged, meshed or smooth.