var Song = Backbone.Model.extend();
var Songs = Backbone.Collection.extend({
model:Song});
var songs = new Songs([new Song({title: "Song 1"}),
new Song({title: "Song 2"}),
new Song({title: "Song 3"})
]);
songs.add(new Song({title:"Song 4"}));
var firstSong = songs.at(0);
var songWithIdC1 = songs.get("c1");
songs.remove(firstSong);
console.log(songs);