question #2 Sahih Muslim 85d, Book 1, Hadith 161 : Why might a narrator choose not to mention a specific name in a hadith transmission?

This hadith has been transmitted by Muhammad b. Bashshar, Muhammad b. Ja’far Shu’ba with this chain of narrators, with the addition that he pointed towards the house of ‘Abdullah, but he did not mention his name for us.