Complex sentence: In later, more developed forms, the shape was held in place by a rigid skirt-shaped structure of steel or whalebone, which in form and function it was very similar to the earlier farthingale.
Split into simpler sentences: In later, more developed forms, the shape was held in place by a rigid skirt-shaped structure of steel or whalebone. In form and function it is very similar to the earlier farthingale.