The camel back sofa’s main design feature is a higher back in the center which descends in a continuous line into the arms of the sofa. There are also designs with two arches on the back.

This type of sofa is also recognized for exposed wood legs  as well as frequently exposed wood on top of the back and arms (although not always).

While a classic design, you can buy contemporary camel back sofa designs (that are a more comfortable than the antique featured here).