Volvox rhymes with:
czechoslovaks, davox, kovach's, magnavox, arnox, bangkok's, benlox, bowersox, clorox, czechoslovaks, davox, hancox, heacox, hecox, hickcox, hickox, hiscox, isaacks, jacox, kovach's, maalox, magnavox, murdoch's, murdock's, murdocks, reebok's, reeboks, shoebox, silcox, wilcox, xerox
Volvox sounds like:
valves, villalobos, villalovos, volvo's, volvos