 The mouth is small and contains one pair of forward-directed, incisor-shaped teeth in the bottom jaw and two pairs in the top jaw.Unlike sharks, which have sharp teeth that are easily replaceable, spotted ratfish teeth are plate-shaped, mineralized, and permanent, which assist them in grinding their prey.Like many bony fishes, but unlike its sister group, the Elasmobranchii, the upper jaw of the chimaera is fused with the skull.