* Egg-shaped is not quite accurate. Elliptical galaxies are more like spherical or ellipsoidal, with varying degrees of flattening. Some are nearly spherical, while others are quite elongated.

* No spiral arms: You're right, elliptical galaxies lack the spiral arms characteristic of spiral galaxies. They generally have a smooth, featureless appearance.

* Interstellar gas and dust: Elliptical galaxies contain far less interstellar gas and dust than spiral galaxies. This is one of the reasons they don't form new stars at the same rate.

In summary: Elliptical galaxies are generally spherical or ellipsoidal, lacking spiral arms and containing significantly less interstellar gas and dust than spiral galaxies.