"When he touched the Mark of any Death Eater, we were to Disapparate, and Apparate, instantly, at his side."
"Hold out your arm," said Voldemort lazily.
Voldemort bent down and pulled out Wormtail's left arm; he forced the sleeve of Wormtail's robes up past his elbow, and Harry saw something upon the skin there ... the Dark Mark. Voldemort examined it carefully, ignoring Wormtail's uncontrollable weeping.
He pressed his long white forefinger to the brand on Wormtail's arm."