While the exact number of dog breeds throughout the world is unknown, the World Canine Organization compiled a registry of all internationally accepted dog breeds. To date, that list contains 339 different breeds. Wow! But, that list does not include the dozens of recognized breeds that no longer exist. Either through breeding these dogs into an entirely new breed altogether, or through lack of interest in maintaining them, here are 13 dogs that no longer grace the globe. A vast majority, however, live on through their ancestry as the basis of many favorite modern breeds.