Mermen

The Merman is the lesser known counterpart of the mermaid.  He seduces humans though not to the extent of

the mermaid.  The merman figures largely in non-western lore - he is present in Indian, Babylonian and Indonesian mythology.  In Ovid's Metamorphosis, Glaucus was a humble fisherman who discovered a magic herb that brought dead fish back to life.  Not knowing its effects on humans, Glaucus tried it and immediately grew a fish tale and became a merman.  He received immortality but had to leave the land for the sea.  He became a demi-god thereafter.  He later fell in love with the beautiful Scylla.  She was repulsed by his features and ran away.  Glaucus asked Circe for a love potion to give to Scylla; however, Circe herself was in love with Glaucus.  He did not return her love and so she punished Scylla by turning her into a horrible sea monster (Metamorphosis - Ovid).

Matthew Arnold (1822-1888) wrote the poem "The Forsaken Merman" about a woman who marries a merman and has children with him but abandons them for a respectable religious existence on the land.  Click the link to read it here: http://bartleby.com/101/747.html