Corpus of Electronic Texts Edition
The Voyage of the Hui Corra (Author: Unknown)

section 57

As they were wending their way, they see three wondrous rivers whereout the birds would come over them, to wit, a river of otters29 and a river of eels, and a river of black swans. And the bird quoth: ‘Let not the shapes which ye see make you sad. For the birds which you behold are the souls of man enduring punishment for the sins they have committed, and there are devils in yon shapes behind them pursuing them,

p.51

and the souls utter heavy and great cries as they flee from their punishment by the devils. Lo, I am leaving you,’ saith the bird; ‘and much knowledge of your goings hath not been vouchsafed to me, and someone else will relate them to you.30’