From Sahih Muslim (Hadith 533):
The same hadith has been narrated from A'mash on the authority of the same chain of transmitters with the exception of these words:You would be no more among men (on the Day of Resurrection) but like a white hair on (the body of) a black ox, or like a black hair on (the body of) a white ox, and he made no mention of: a strip on the foreleg of an ass
Reference: Muslim 533