Salmar

A Maia of the people of Ulmo, who entered Arda with his lord, and was the maker of Ulmo's famed Ulumúri, his horns wrought from white shell. The music of the Ulumúri would awaken a longing for the sea in the hearts of all those who heard them.

Salmar has a very minor part to play in the published Silmarillion (indeed, he is mentioned just once in the entire work). In earlier versions of the tales, however, he is a much more important figure, and at one point is even identified as one of the Valar. In the The Book of Lost Tales (volumes I and II of The History of Middle-earth) he is a great musician with skill in playing many instruments, explaining his role in the making of Ulmo's fabled horns. The Lost Tales have much more to say about him, too: there we find that he had a twin brother Ómar, and was at one time Ulmo's only companion in the deeps of the Outer Ocean (though other stories make him a resident of the city of Valmar). He fought alongside the Valar in the Battle of the Powers, and by one account he was present at the moment when Melkor was finally taken captive at the end of that Battle.

All of this detail was abandoned by Tolkien in later forms of the story, and Salmar was reduced to a barely-mentioned Maia of Ulmo whose only known role was to make the Ulumúri for his master. Much of the older history of Salmar actually fits quite easily into the later conception (for example, it's quite possible to imagine that Salmar was a skilled musician, or that he fought in the Battle of the Powers) but if he played any larger part in the story, there is no evidence remaining in the text of the Silmarillion.