Commentary Inf XXXIV 133-138

There is no pausing for rest that now seems a waste of time, given the nearness of the light. Looking through a crevice (the word in Italian is pertugio, the same word used to describe the opening through which Ugolino could see the moon from his cell [[Inf XXXIII 22]]) in the earth's surface, whence, we assume, comes the little stream that they are following, Dante is able to see a few stars in the firmament above him.