Whats an auxilary shaft??

just like the title says...what the hell is the auxilary shaft? i got a call from the machine shop asking if wanted the two auxilary bearings put in or i wanted to do it myself...and i asked them how much and they say 5 bucks per bearing....so i said fine go ahead and they said i needed to bring the auxilary shaft in so they can balance it or whatnot.....

i looked in the tsrm but i didnt see any auxilary shaft in the block or head.... is that another name for the oil pump driveshaft??

any help? i know it sounds stupid but i really dont feel like calling and asking them to explain what they mean...lol.....pride thing i guess hehe.......

thanks guys!