Page:The Osteology of the Reptiles.pdf/85

Rh The squamosal normally articulates with the tabular and quadrate posteriorly, anteriorly with the postorbital, and often, both in the lizards and mosasaurs, by a slender prolongation with the tip of the jugal; very rarely, as in Uromastix, with the jugal only. In some lizards it has suffered reduction, and is absent in the Geckonidae, Anniella, and Amphisbaenidae, vestigial in the Helodermatidae.



. 54. Mosasaur skulls: Upper figure, Clidastes, from the side; middle figure, Platecarpus, from below; lower figure, Tylosaurus, from above. an, angular; bs, basisphenoid; c, coronoid; ep, epipterygoid; fr, frontal; j, jugal; l, lacrimal; m, maxilla; na, nasal; oc, occipital condyle; pa, parietal, palatine; pm, premaxilla; pf, prefrontal; pt, pterygoid; po, postorbital; q, quadrate; sp, splenial; sq, squamosal; tr, transverse; v, vomer.