rex 
(rĕks)
(rĕks)n.
A mammal, such as a rabbit or cat, having a genetic mutation that causes the guard hairs to be short or lacking, often resulting in a curly coat.
[From French (lapin) rex, rex (rabbit), name given to a breed of rabbit developed in France between 1919 and 1924 that displayed the mutation, from Latin rēx, king; see reg- in the Appendix of Indo-European roots.]
rex adj.