. Breviora. BREVIORA No. 389 Figure 1. The skull in dorsal view. This and the following skull figures are based mainly on ISICZ 4117 XI. Abbreviations for Figs. 1 to 5: a, articular; an, angular; c, coronoid; d, dcntary; ec, ectopterygoid; /, frontal; /, jugal; I, lacrimal; m, maxilla; n, nasal; p, parietal; part, prearticular; pf, postfrontal; pw, premaxilla; po, postorbital; popr, paroccipital process; pp, postparietal; prj, prefrontal; pt, pterygoid; q, quadrate; qj, quadratojugal; san, surangular; soc, supraoccipital; sp, splenial; sq, squamosal. the V pointing anteriorly. Here, how
. Breviora. BREVIORA No. 389 Figure 1. The skull in dorsal view. This and the following skull figures are based mainly on ISICZ 4117 XI. Abbreviations for Figs. 1 to 5: a, articular; an, angular; c, coronoid; d, dcntary; ec, ectopterygoid; /, frontal; /, jugal; I, lacrimal; m, maxilla; n, nasal; p, parietal; part, prearticular; pf, postfrontal; pw, premaxilla; po, postorbital; popr, paroccipital process; pp, postparietal; prj, prefrontal; pt, pterygoid; q, quadrate; qj, quadratojugal; san, surangular; soc, supraoccipital; sp, splenial; sq, squamosal. the V pointing anteriorly. Here, howe\er, in contrast to normal advanced forms, the forward push of the V is so pronounced that the upper limb of the V is in contact with the postorbital and jugal; as a consequence the upper half of the fenestra is completely closed, the opening remaining being a ventral triangu- lar area. A similar situation is present in the aetosaurs. The premaxillae are thickened ventrally, with accommodation for tooth roots. Anteriorly each element sends a slender process upward to meet the nasal medial to the narial openings. Pos- teriorly the premaxilla sends a stout process upward to form part of the posterior border of the naris. A pronounced ridge extends backward on either side of the skull roof along the upper margin of the antorbital region toward the upper anterodorsal margin of the orbit; this pair of ridges, formed anteriorly by the nasals, sharply separates the flattened dorsal surface of the skull from the essentially \ertical lateral surfaces. Below this rids^e the nasal extends downward to form the upper boundary of the naris. This flange is in contact with the premaxilla ventrally, both in front of and behind the naris. On the dorsal surface the nasals extend well backward, broad-. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resem
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Keywords: ., bookauthorharvarduniversitymuseumofcomparative, bookcentury1900
