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Show 1895.] LORIUS F L A V O P A L L I A T U S A N D PSITTACUS ERITHACUS. 365 and the palatines also diverge slightly more ventrad. The mandible has its antero-dorsal margin more angular instead of rounded, resembling a very obtuse pointed arch inverted (see figs. 18 & 19, p. 393). It differs also in not having lateral defects of ossification and in the less relatively vertical extent of the most postaxial part of each ramus. T B E G E N E R A L POSTERIOR ASPECT of the skull (see fig. 11, p. 385) presents us with a dorsal margin more flattened than in P. erithacus. Its surface is less concave medianly and less convex on either side of such concavity. The palatines diverge slightly more ventrad, and between them the bony beak shows a sudden narrowing between the lateral tooth or notch of either side, and ventrad of this it is narrower and more pointed. The quadrates jut out slightly less instead of decidedly more than the postorbital processes, and the middle of the occiput, just above the relatively somewhat wider foramen magnum, presents a rounded more marked convexity from side to side. The apex of the mandible seems more prolonged, showing more of the ventral surface of the relatively more extensive symphysial portion. Detailed Description. I. T H E BONY BEAK OR PROSOPIUM 2 The prosopium, when VIEWED LATERALLY (see fig. 1), shows a dorsal margin which descends preaxiad in front of the nares, less sharply than in P. erithacus, though from just over the tooth on the ventral, or tomial, margin it arches even more rapidly; so that the apex of the prosopium descends rather more vertically, while it is proportionally narrower antero-posteriorly, where it begins to project ventrad of the line of the tomial margin, and is more pointed towards and at its apex. From a little in front of the preaxial margin of the nares back to the articulation of the prosopium with the cranium, the dorsum thus viewed is almost straight. The nares are each longer antero-posteriorly and seem narrower dorso-ventrally because they look more upwards and less outwards than in P. erithacus. Their preaxial margin rises as a somewhat more marked ridge, while the surface of the prosopium in front of and below each nostril presents no depressed fossa. In P. erithacus, on the other hand, there is (see fig. 2) just in front of and below each nostril a depressed area (da), the greatest breadth of which is more than two-thirds the diameter of the nostril, and is bounded below by a very marked groove which runs postaxiad to the postaxial border of the nostril, which border may be perforated by a series of small foramina, or these may be replaced by notches as in L. flavopalliatus. By this term I intend to denote the whole ossified mass in front of the cranio-facial articulation and the articulations of the zygomata and palatines. It includes the premaxilla, the maxillae, maxillo-palatine processes, the nasals, and the ethmoidal and turbinal ossifications of the beak. |