[]とnew Arrayは違う？ UnityScript

これはOK

var numAry = new Array();
numAry[0] = [1, 3, 5, 4, 9];
numAry[1] = [1, 4, 6, 2];
numAry[2] = [1, -2, -3];

なぜかこれはだめ

var numAry = [];
numAry[0] = [1, 3, 5, 4, 9];
numAry[1] = [1, 4, 6, 2];
numAry[2] = [1, -2, -3];