As the web-site that Jim supplied shows, nighean Gobha 'n D`ine" means the daughter of the Smith of the Dun" literally. This is what is described as the Genitive Case (Possessive) for the Gaelic words Gobha and Dun.

In the Dun, the i and e are added as part of the change to the Genitive. Gobha doesn't due to starting with g and ending with a