Elliptical galaxies are subclassified according to how flattened they appear. Note that the above classification scheme for elliptical galaxies is fairly lame, since it relies on the projected shape of the galaxy not on the true three-dimensional shape. The projected shape of an object depends on the angle from which we view it, which is totally accidental. Since elliptical galaxies appear elliptical in the sky, they must be ellipsoidal in three dimensions. Just as an ellipse is a distorted circle, an ellipsoid is a distorted sphere.
Elliptical galaxies are probably a mix of all three shapes.
Elliptical galaxies have a very large range of sizes. Both the largest and smallest galaxies in the universe are elliptical. Giant elliptical galaxies contain 1 trillion stars or more. Dwarf ellipticals contains 10 million stars or less. Of the two dozen galaxies closest to us, a dozen are dwarf ellipticals.