For ten points,identify this close relative of the hagfishes, one of the most primitive chordates.
Almost unchanged since the Ordovician, these animals have a cartilaginous braincase and a large notochord.  Distinguished from the Gnathostomata by their lack of jaws, the mouth contains a raspy tongue which draws blood after the animal's sucker attaches itself to a host.  For ten points,identify this close relative of the hagfishes, one of the most primitive chordates.
Almost unchanged since the Ordovician, these animals have a cartilaginous braincase and a large notochord.  
lamprey