Merrow
The merrows supposedly require a magical cap (Irish: cochaillín draíochta; anglicised: cohuleen druith) in order to travel between deep water and dry land.
A number of other terms in Irish are used to denote a mermaid or sea-nymph, some tracing back to mythological tracts from the medieval to the post-medieval period.
Croker's material on the merrow was to a large measure rehashed by such authors on the fairy-kind as Thomas Keightley, John O'Hanlon, and the poet William Butler Yeats.
[29][g] But after some "years in succession" they will almost inevitably return to the sea, their "natural instincts" irresistibly overcoming any love-bond they may have formed with their terrestrial family.
Another researcher noted that the Irish merrow's device was her cap "covering her entire body", as opposed to the Scottish Maid-of-the-Wave[h] who had her salmon-skin.
[33] One stymied investigator conjectured this claim to be an extrapolation on Kennedy's statement that sea-cows are attracted to pasture on the meadowland wherever the merrow resided.
[35] While most stories about merrow are about female creatures, a tale about an Irish merman does exist in the form of "The Soul Cages", published in Croker's anthology.
[37][38] The male merrow in the story, called Coomara (meaning "sea-hound"[39]), has green hair and teeth, pig-like eyes, a red nose, grows a tail between his scaly legs, and has stubby fin-like arms.
The notion that the cohuleen druith is a hat "covered with feathers", stated by O'Hanlon and Yeats[28][6] arises from taking Croker too literally.
As other commentators have point out, what Croker meant was that both contained the motif of a supernatural woman who is bereft of the article of clothing and is prevented from escaping her captor.
An analogue to the "mermaid's cap" is found in an Irish tale of a supernatural wife who emerged from the freshwater Lough Owel in Westmeath, Ireland.
[56] It did not escape the notice of 19th century folklorists that attestations of murdúchann occur in Irish medieval and post-medieval literature, although they have been somewhat imprecise in specifying their textual sources.
Croker's remark that "the romantic historians of Ireland" depicted suire (synonym of merrow) playing round the ships of the Milesians[4] actually leads to the Book of Invasions, which recounts siren-like murdúchann encountered by legendary ancestors of the Irish people while migrating across the Caspian Sea.
O'Hanlon's disclosure of "an old tract, contained in the Book of Lecain [sic]" about the king of the Fomorians encountering them in the Ictian Sea[35] is a tale in the Dindsenchas.
[17] The medieval Lebor Gabála Érenn ("The Book of Invasions") relates how a band of Goidels on a migratory voyage were stalled on the Caspian Sea by murdúchand (translated as "sirens" by Macalister) who lulled them to sleep with their songs.
Even though Caicher the Druid is present in either case, different sets of voyagers, generationally-shifted from each other are engaged in actions with the sirens, depending on the variant text groups.
However, Michael O'Clery's 17th century recension of the Book of Invasions interpolated a decidedly half-fish half-female depiction of the murdúchand in his copy of the Lebor Gabála: In this wise are those seamonsters, with the form of a woman from their navels upwards, excelling every female form in beauty and shapeliness, with light yellow hair down over their shoulders; but fishes are they from their navels downwards.
One tale explains how the demise of Roth son of Cithang[o] by mermaids (murduchann) in the Ictian sea (English Channel) gave birth to the name Port Láirge (now County Waterford).
[s][70] There are several onomastic tales which attempts to explain the name origin of Ess Ruaid (Assaroe Falls), one of which involves mermaid music (samguba).
[65][71] Nine women dwelling in the sea held immobilized the fleet of three ships led by Rúad son of Rígdonn, a grandson of the king of the Fir Muirig people.
