Samuel Wendell Williston,
The Osteology of the Reptiles
(1925)
“ The skull of the ichthyosaurs, while retaining not a few primitive characters, has been highly and peculiarly modified in many ways. The greatly elongated premaxilla, unlike those of other aquatic reptiles, is broadly separated above by the very large nasal, and bears numerous teeth; the maxillae are short. All bones are paired. The frontals are small. The very large orbits have the usual bounding bones, prefrontal, postfrontal, postorbital, jugal, and lacrimal, but their relations are somewhat changed. ”
