Reverend Optimus Grey
Optimus: Latin, “very good,” “best.” A fitting first name for the Reverend Grey, given how highly Mrs. Proudie thinks of him. Perhaps Trollope is humorously suggesting that he is the “best” at being grey. [JM 2005]
she of the Argus eyes
Mrs. Proudie is likened to the watchful, hundred-eyed monster of Greek myth. Argus was charged by Hera to watch over Io, whom Zeus had turned into a cow in order to hide the fact that he was committing adultery with her. It was Argus’ job to ensure that this adultery ceased. Mrs. Proudie is in this case watchful in that she has noticed the absence of one of the servants during family prayers. [JM 2005]
What changeable creatures you men are!
Compare Aeneid 4.569: varium et mutabile semper / femina. “An always changing and fickle thing is woman.” Trollope has elsewhere used Classical allusions to attribute qualities widely considered feminine to his male characters; this could be another such instance. [JM 2005]
Sources: Vergil, Aeneid 4.569-570.