whiskers, bristles on the jaws of an animal
髵 centers on coarse facial hair on an animal's lower jaw: whiskers or bristles around the mouth.
髵 combines 髟 (hair) with 而, which likely contributes the sound and may relate to the jaw or whiskers. The exact historical development is uncertain.
The top 髟 means hair, and the bottom 而 looks like a jaw with bristles. Picture long whiskers growing from an animal's jaw.
For ジ, imagine a giraffe with long whiskers on its jaw: giraffe -> ジ, and the whiskers match the kanji's meaning.