Hi I see that Hammerhead Worms are known in America but I have never seen one or heard of one until this morning when I found one in the garden.
Are they common residents?
I live in Barberton, Mpumalanga, South Africa.
The occurence of Hammer head worms in South Africa
I find one occasionally in my garden in Thailand, which is its natural place of origin. They also eat earthworms and are considered to be a pest although they also eat insect larvae and molluscs. They seem to be popping up all over the world now.
http://davesgarden.com/guides/bf/go/1839/