In cetaceans, the nose has been reduced to the Nostrils.

http://en.wikipedia.org/wiki/Nose

 In cetaceans, the nose has been reduced to the nostrils, which have migrated to the top of the head, producing a more streamlined body shape and the ability to breathe while mostly submerged. Conversely, the elephant's nose has elaborated into a long, muscular, manipulative organ called the trunk.