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Show 1895.] LORIUS FLAVOPALLIATUS AND PSITTACUS ERITHACUS. 389 species, indeed in L. flavopalliatus it would be almost perfectly straight but for the fossa for the geniohyoid and the transverse prominence in front of it. A faintly marked curved line (convex postaxiad in P. erithacus with a sigmoid flexure, concave postaxiad above and convex postaxiad below in the other species) descends- from the dentary process in P. erithacus, from behind the dentary process in L. flavopalliatus-to the dorsal margin of the fossa for the genioglossus (gg). This fossa is much more marked in L. flavopalliatus, aud, on account of the length of the symphysis, relatively nearer the postaxial margin of the bone. In P. erithacus it is twice Fig. 12. Lateral aspect of mandible of Psittacus erithacus. a. Articular prominence. pa. Postarticular process. ag. Angular process. pc. Postcoronoid process. c. Coronoid process. pp, Prearticular process. d. Dentary process. Fig. 13. Lateral aspect of mandible of Lorius flavopalliatus. (Lettering the same as in fig. 12.) or more as distant from its anterior margin as from the posterior one, and it is bounded supero-anteriorly by an arched ridge, concave backwards, just beneath which are one or two vascular foramina. The fossa is wider and more shallow than in L. flavopalliatus, and bounded infero-posteriorly by a bony ridge which constitutes the postero-inferior margin of the symphysis (see figs. 16 & 17). In L. flavopalliatus it is bounded supero-anteriorly by a very delicate lamina of bone, in front of which is a rather wide transverse prominence convex antero-posteriorly. Behind the fossa there is a smooth portion of bone intervening between it and the postaxial margin of the symphysis. |