Alien invaders poised to destroy Boston?

The Urban Pantheist discovers specimens of the dreaded terrestrial flatworms along the Muddy River. Now he awaits word from experts at Harvard as to whether Boston is cold enough to keep these predatory worms from Asia from decimating the local ecosystem (by gorging on earthworms), as they are now doing in Ireland:

... Flattened and flaccid, yet muscular and sluglike, secreting a thick sticky mucus, and, when disturbed, forever waving its mushy little hammerhead around, it's certainly distinctive. Unlike its more famous relatives that spend most of their lives inside the bodies of other animals, this creature and its ilk feed on earthworms, tackling prey many times their own size. ...

Oh, yes, he's keeping a pickled specimen on his mantel.