Analysis of Cramped in That Funnelled Hole

Cramped in that funnelled hole, they watched the dawn
Open a jagged rim around; a yawn
Of death's jaws, which had all but swallowed them
Stuck in the bottom of his throat of phlegm.

They were in one of many mouths of Hell
Not seen of seers in visions, only felt
As teeth of traps; when bones and the dead are smelt
Under the mud where long ago they fell
Mixed with the sour sharp odour of the shell.