Back in 1973 or so Roddenberry's company Lincoln Enterprises sold bios of the animated series characters. Since I knew the main characters, the only two I bought were those of the two new aliens, Arex and M'ress. I'll post M'Ress next time; first, we look at the biographical information on the odd-looking (to us) tripodal Arex, who was voiced (as almost all non-regular characters were) by James "Scotty" Doohan.
Although designed to be more alien-looking than any character could ever have been done on the live-action show (an advantage of the animated format) Arex was never used as more than window-dressing; all we ever saw of him was seated at navigation and pushing buttons. I can't remember ever having seen him even stand, much less walk and do anything. He was so underused that he made Uhura look like a top-billed co-star by comparision.Bonus: Below is the front and back of the assembly directions that came in the "Space Ship Set" by AMT, which came out in the mid 70's. Each ship was small, only about 5 inches at the longest; this set was fragile on its base and it didn't last long over our many moves. I think all I have left, other than this sheet, is the fuselage of the Klingon ship.