_Ossification in otic and occipital regions._--The otic region of the cranium is largely unossified. At the level of the optic foramen (Fig. 14) the floor of the neurocranium is cartilaginous but completely underlaid by the bony parasphenoid. The taenia tecti marginales and the tectum synoticum are covered dorsally and laterally by the frontoparietals. Perichondral ossification representing the prootic bone occurs at the margin of the optic foramen and somewhat posteriorly over part of the floor of the neurocranium. Perichondral and endochondral ossification occurs in the sides of the neurocranium ventral to the lamina perpendicularis. This ossification expands laterally until it meets the crista parotica dorsolaterally and forms the dorsal part of the prootic bone. The anteroventral edge of the otic capsule remains cartilaginous. Posteriorly, at the level of the anterior acoustic foramen, endochondral ossification is meager and restricted to the dorsomedial parts of the otic capsule, plus a small amount in the neurocranial floor; perichondral ossification is restricted to the peripheral areas showing endochondral ossification. Posteriorly, endochondral ossification is restricted in the dorsal part of the otic capsule but somewhat increased in the floor of the capsule. The lateral part of the otic capsule posterior to the terminus of the operculum and the ventromedial and dorsomedial parts of the neurocranium remain unossified. Articular Region In the anterior sections (at the level of the oculomotor foramen) the angulosplenial (_angspl._) is a moderate-sized bone (Fig. 15). Meckel's cartilage (_Mc. c._) is present as a small ovoid cartilage lying dorsolateral to the angulosplenial. Posteriorly, Meckel's cartilage is dorsal to the angulosplenial. The cartilage increases in size at the level of the posterior acoustic foramen, and the angulosplenial decreases in size posteriorly. At the level of the posterior border of the posterior acoustic foramen, the maxillary terminates and is replaced by the quadratojugal. The quadratojugal, ventral arm of the squamosal, pterygoid process, pterygoid, and Meckel's cartilage converge. At the level of the jugular foramen (_jug. f._) (Fig. 19) the quadratojugal is incorporated into the squamosal-pterygoid process-pterygoid complex. The complex is narrowly separated by connective tissue from Meckel's cartilage ventrally. The quadrate process (_quad. proc._) is represented by the cartilage bordered dorsally by the pterygoid process and the ventral arm of the squamosal, and ventrally by Meckel's cartilage. At the posterior terminus of the skull all bony elements of the articular region terminate, except for a small terminal part of the angulosplenial underlying Meckel's cartilage. SUMMARY