The Breton mermaids. They are conjectured by Rhys in Celtic Folklore to be the same as the Welsh morgans.

There is a mysterious story about the Morgan who was supposed to haunt the Lake Glasfryn Uchafin the parish of Llangybi. It is one of quite a number of lakes which were said to have burst forth from a covered well when the cover had been removed and the well exposed. Rhys, in Celtic Folklore (vol.I, pp.365-376), carefully explores all the various forms in which he received the legend. The one that he finds of special interest is that of the Morgan, which is said to come from the lake and carry away naughty or over-adventurous children. He believes that the Morgan was originally a mermaid of the same breed as the Breton morgens and connected with Morgan Le Fay. 'Morgan' in Welsh, however, was always a man's name, and Rhys suggests that the water spirit became male in this tradition because of the Welsh usage.

[Motifs: F420.1.1; F420.1.2*]