咬將下來 He Bites It Clean Off
那駙馬見不停當，在山前打個滾，又現了本像，展開翅，旋繞飛騰。二郎即取金弓，安上銀彈，扯滿弓，往上就打。那怪急鎩翅，掠到邊前，要咬二郎。半腰裡才伸出一個頭來，被那頭細犬攛上去，汪的一口，把頭血淋淋的咬將下來。那怪物負痛逃生，徑投北海而去。那驸马见不停当，在山前打个滚，又现了本像，展开翅，旋绕飞腾。二郎即取金弓，安上银弹，扯满弓，往上就打。那怪急铩翅，掠到边前，要咬二郎。半腰里才伸出一个头来，被那头细犬撺上去，汪的一口，把头血淋淋的咬将下来。那怪物负痛逃生，径投北海而去。
逐句解 Line by line
The son-in-law, seeing that things were not going well, took a roll before the mountain, showed his true form once more, spread his wings and went wheeling up into the air.
當 at 停當 is dàng, settled or in order, where pypinyin gives the temporal dāng — the same graph took dàng at 極當 and dāng twice elsewhere in the last few passages. 不 keeps bù before the rising 停 tíng, which the spec on 當 does not disturb.
Erlang at once took his golden bow, fitted a silver pellet, drew the bow full and shot upward at him.
彈 is dàn, a pellet — the noun — against the tán of plucking or shooting. The golden bow and silver pellets are Erlang's standing equipment, and this is the only weapon in the chapter that is fired rather than swung.
The monster hastily furled its wings, swept down close, and made to bite Erlang.
那 is deictic. 鎩 is to have the wing-feathers cut or laid flat, so 鎩翅 is to fold the wings down for a stoop rather than to be injured. The creature is answering an arrow by closing the distance.
It had just put out a head from the middle of its body when that slender hound sprang up at it and with one bark bit the head clean off, dripping with blood.
血淋淋 is a registered phrase and takes 血 at xiě against the xuè the graph carries in isolation. It is the only place in the chapter where the context reading and the isolated default part company, and the chapter's other 血 in this same block, a hundred and eighteen graphs later, takes the ordinary xuè. 咬將下來 takes 將 as the verbal infix.
The monster bore its pain and fled for its life, making straight away for the Northern Sea.
那 is deictic. 負痛逃生 repeats word for word what the two maimed fiends did at the very start of the chapter, when Pilgrim cut off an ear and a lip and sent them home. The chapter's fourth and last flight uses the phrasing of its first.
The tenth head is the point of the whole sequence, and the novel has been holding it since the middle of the chapter. It came out once before, without warning, from the middle of the body, and took Eight Rules by the mane. It comes out from the same place here, and this time something is waiting for it.
What is waiting is a dog. Erlang's pellet misses — the text does not even say it misses, it simply moves on — and the creature is close enough to bite him when the hound goes up. One bark, and the head comes away. The most decisive act in a chapter of gods and immortals is performed by an animal in four graphs.
The flight that follows is described in the words the chapter opened with. 負痛逃生, bearing the pain and fleeing for life, was what the two lesser fiends did after Pilgrim mutilated them and sent them home with a message. It is now what the Nine-Headed Worm does, mutilated in the same way and going in the opposite direction.