. Bulletin of the British Museum (Natural History) Geology Supplement. ESPECIALLY MYCTOPHOIDS. art Fig. 36. Enchodus lewesiensis (Mantell). Hyopalatine bones and mandible of the left side in medial view. pterygoid expands medially in front of the endopterygoid, so that both sides of the V-shaped trough are formed of ectopterygoid. The trough widens anteriorly into a U-shape, and the postero-ventral region of the palatine rests within it. On the ventro-lateral region of the palatine bone there is a longitudinal ridge pro- jecting laterally and ventrally. The ectopterygoid spreads anteriorly, ve
. Bulletin of the British Museum (Natural History) Geology Supplement. ESPECIALLY MYCTOPHOIDS. art Fig. 36. Enchodus lewesiensis (Mantell). Hyopalatine bones and mandible of the left side in medial view. pterygoid expands medially in front of the endopterygoid, so that both sides of the V-shaped trough are formed of ectopterygoid. The trough widens anteriorly into a U-shape, and the postero-ventral region of the palatine rests within it. On the ventro-lateral region of the palatine bone there is a longitudinal ridge pro- jecting laterally and ventrally. The ectopterygoid spreads anteriorly, ventral to this ridge and articulates with its undersurface. Ventrally the ectopterygoid bears a row of large teeth which decrease in size posteriorly. The anteriormost ectopterygoid tooth arises from the ventral edge of the bone. Farther back along the ectopterygoid, the endopterygoid projects below the suture line between the two bones so that the more posterior teeth of the ectopterygoid series tend to arise from the ventro-lateral surface. The bases of the teeth are angled in such a manner as to make the main body of each tooth hang vertically downwards. There are approximately 7 functional teeth present on the ectopterygoid at any one time, and replacement teeth are visible close to the functional ones. All of the teeth are elongated and needle-like with well defined, but not particularly expanded bases. The teeth are laterally compressed to give rise to two cutting edges which are not strictly anterior and posterior, but set somewhat obliquely to the long axis of the ectopterygoid, and have a slightly recurved aspect. The endopterygoid is visible from the lateral aspect as a small strip of bone below the region of fusion with the ectopterygoid. The endopterygoid bears a marginal row of minute teeth. On the internal face of the endopterygoid several more rows of minute teeth are seen radiating forwards and upwards. The more dorsal region of the endopterygoid inclines mediall
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