The Salty Dog was created in the 1950's by George Jessel and is closely related to the Greyhound Cocktail distinguished by the glasses salted rim like the Margarita and Paloma.

The Salty Dog Cocktail Recipe
Ingredients
2 oz of gin
3 oz of freshly squeezed grapefruit juice (white or pink)
salt
Garnish with a slice/wedge of grapefruit
Assembly
Rub the edge of a tall glass with a piece of grapefruit, then dip the edge of the glass into some salt. Add the gin and grapefruit juice, stir well, then add ice to fill. Fix a small slice of grapefruit to the edge of the glass as a garnish.