E. Cobham Brewer 18101897. Dictionary of Phrase and Fable. 1898.
Pistris, Pistrix, Pristis, or Pristrix.
The sea-monster sent to devour Andromeda. In ancient art it is represented with a dragons head, the neck and head of a beast, fins for the forelegs, and the body and tail of a fish. In Christian art the pistris was usually employed to represent the whale which swallowed Jonah. (Aratus: Contmentaries.) Aratus died A.D. 213.