What is commonly referred to as a cantaloupe is actually a species of muskmelon; cantaloupe is just a different name for the Cucumis melo reticulatus muskmelon. There is also a variety called a European cantaloupe that is a muskmelon as well.
Although both the American and European varieties of cantaloupe are muskmelons, the opposite is not always true. There are types of muskmelons that are not cantaloupes, such as the Bender, Casaba and Honey Dew.
Muskmelons originated in Persia hundreds of years ago. They slowly spread through the Middle East and Europe and eventually found their way to North America.