In Rhys's Preface to Malory's Morte Darthur, pp. xxv., xxviii., xxix., I find the following remarks on a savage cat of Celtic tradition:—"In an obscure 'poem consisting of a dialogue between Arthur and Glewlwyd Gavaelvawr,' occurs at the end of the fragment the following passage, in which Kei is represented as fighting with a great cat:—

Worthy Kei went to Mona
To destroy lions.
His shield was small
Against Palug's Cat.
When people shall ask
'Who slew Palug's Cat?'
Nine score...
Used to fall for her food.
Nine score leaders
Used to...

The manuscript is imperfect, and it breaks off just where one should have heard more about Cath Palug, or 'Palug's Cat,' a monster, said in the Red Book Triads to have been reared by the Sons of Palug, in Anglesey." (Merlin, Wheatley, v.2, 1899)