The following passage is from the Call of the Wild. What do "drew" and "clip" mean?
And Buck was truly a red-eyed devil, as he drew himself together for the spring, hair bristling, mouth foaming, a mad glitter in his bloodshot eyes. Straight at the man he launched his one hundred and forty pounds of fury, surcharged with the pent passion of two days and nights. In mid air, just as his jaws were about to close on the man, he received a shock that checked his body and brought his teeth together with an agonizing clip. He whirled over, fetching the ground on his back and side. He had never been struck by a club in his life, and did not understand.
I'd appreciate your help.