Merrow (from Gaelic murúch) or Murrough (Galloway) is the Scottish and Irish Gaelic equivalent of the mermaid and mermen of other cultures. There are other names pertaining to them in Gaelic: Muir-gheilt, Samhghubha, Muidhuachán, and Suire. They would seem to have been around for millennia because according to the bardic chroniclers, when the Milesians first landed on Irish shores the Suire, or sea-nymphs, played around them on their passage.
Merrow are said to appear as humans from the waist up and as fish from the waist down. Said to be gentle, modest, affectionate and benevolent, the merrow is believed to be capable of attachment to human beings and there have been reports of inter-marriage. However, most often, the creatures return to their former homes beneath the sea. Merrow-maidens have also been known to lure young men beneath the waves, where afterwards the men live in an enchanted state. In most cases, the female merrow had a red “cap” or “cape,” and if a human could capture and hide this possession from the merrow, then she would remain on land without problem. Yet, if the “cap” or “cape” were ever found by the merrow, she would have then felt compelled to return forever to the ocean, possibly leaving entire families behind.
Merrow wear a special hat called a cohuleen druith, which enables them to dive beneath the waves. If they lose this cap, it is said that they will lose their power to return beneath the water. Merrow are also known to leave their outer skins behind, in order to transform into other beings more magical and beautiful. The merrow has soft white webs between her fingers, and she is often depicted with a comb parting her long green hair on either side. In Celtic lore, merrow music is known to be heard coming from just beneath the waves.
An old tract found in the Book of Lecain stated that a king of the Fomorians, when sailing over the Ictean sea, had been enchanted by the music of sea-maids until he came within reach of these sirens—then they tore his limbs asunder and scattered them on the sea. From Dr. O'Donovan's Annals of the Four Masters—entered in the year 887 A.D.—there was a curious tale of a mermaid cast on the Scottish coast—Alba. She was 195 feet (59 m) in length and had hair 18 feet (5.5 m) long; her fingers were 7 feet (2.1 m) long as was her nose, while she was as white as a swan. Most stories about merrow are about female creatures; however, some tales about mer-men do exist. In these tales, mer-men captured the souls of drowned sailors and locked them in cages under the sea. While female merrow were considered to be very beautiful, the mermen were thought to be very ugly. This fact potentially accounted for the merrow’s desire to seek out men on the land.