. Bulletin of the British Museum (Natural History) Geology Supplement. FOSSIL AND RECENT EHhm 103. dpal eart 10mm Fig. 50. Osmeroides lewesiensis (Mantell). Hyopalatine bones, opercular series (stippled) and mandible of the left side in medial view. Composite of several specimens. plate bears numerous small villiform teeth of regular size. The vomer bears a large tooth plate which is partially divided into lateral halves ; the teeth are similar to those on the parasphenoid. Hyopalatine bones. The hyopalatine bones are stout and firmly united to one another, forming a rigid roof to the
. Bulletin of the British Museum (Natural History) Geology Supplement. FOSSIL AND RECENT EHhm 103. dpal eart 10mm Fig. 50. Osmeroides lewesiensis (Mantell). Hyopalatine bones, opercular series (stippled) and mandible of the left side in medial view. Composite of several specimens. plate bears numerous small villiform teeth of regular size. The vomer bears a large tooth plate which is partially divided into lateral halves ; the teeth are similar to those on the parasphenoid. Hyopalatine bones. The hyopalatine bones are stout and firmly united to one another, forming a rigid roof to the buccal cavity. The hyomandibular is broad and articulates with the neurocranium by a large head which is separable into swollen anterior and posterior regions. The lateral surface is marked by two ridges which originate from the articulatory regions and converge ventrally to form a single stout ridge running the length of the hyomandi- bular shaft. The medial surface of the hyomandibular is marked by a prominent groove which leads ventrally to a large foramen. This in turn leads to a canal opening beneath the opercular process on the posterior edge. The groove, foramen and canal mark the path of the hyomandibular trunk of VII and the efferent hyoidean artery. Anteriorly the head of the hyomandibular is produced as a thin wing which is partially covered ventrally by the metapterygoid. The metapterygoid is large and irregularly shaped. Posteriorly and ventrally it lies in the vertical plane but antero-dorsally it twists horizontally to lie in con- tinuity with the endopterygoid. Contact with the quadrate was mediated by cartilage, but with other bones union was syndesmotic. Dorsally, where it overlaps the hyomandibular, a cup-shaped depression is formed which received part of the levator arcus palatini muscle. The quadrate is fan-shaped and has a deep ' V '-shaped notch which received the pointed end of the symplectic. The anterior border of the quadrate is thin and fits. Please
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