Odontolcae \O`don*tol"cae\, n. pl. [NL., from Gr. 'odoy`s, 'odo`ntos, a tooth + ? a furrow.] (Paleon.) An extinct order of ostrichlike aquatic birds having teeth, which are set in a groove in the jaw. It includes {Hesperornis}, and allied genera. See {Hesperornis}. [Written also {Odontholcae}, and {Odontoholcae}.]