They were scripted as Caitians but, in interviews, the actresses described being put in all manner of appliances that weren't used, including felinoid ears. So just 'cos the script says they're Caitians doesn't mean they are. Similarly, the Andorian thrall in James Blish's novelization of "Gamesters of Triskelion" is a red-skinned alien with a flap of flesh for a nasal covering (perhaps originally scripted that way?), and Thelin the Andorian of "Yesteryear" is scripted as blue, not grey. Billy Van Zandt's species was described in publicity materials as "a Rhaandarite", but originally scripted as a "high-domed Vegan", and the actor didn't know of the Rhaaandarite term being coined until the commercial material started coming out for the film's premiere. During filming, he was a Vegan and a "Bumphead".