| OCR Text |
Show 1895.] LORIUS FLAVOPALLIATUS AND PSITTACUS ERITHACUS. 371 piece which bears the ascending median ridge and the two concavities on either side of it. Towards the dorsal end of each lateral margin is a short but sharp dorsal process (dp), so that a notch is formed on either side of the uppermost part of the median ossification just before it merges into the horizontal osseous bar which forms the dorsum of the hinder aspect of the prosopium. In Lorius flavopalliatus the posterior surface of the prosopium is relatively as well as actually much less dorso-ventrally extended ; the posterior nares are more nearly horizontal and much less inclined ventrad externally; the lachrymal processes are shorter and especially less produced dorsad, and tbe lateral processes are larger (instead of smaller) than the median ones, and descend ventrad much beyond (instead of much less than) the median ones. II. THE CRANIUM. THE LATERAL ASPECT of the cranium (see figs. 1 & 2) shows-addition to what has been said as to the lateral aspect of the skull as a whole-the following characters. At the dorsal part of its preaxial margin the nasal process of the frontal (np) is less conspicuous in L. flavopalliatus than in P. erithacus. Of tbe margin of the interorbital septum its dorsal part does not form so marked an angle with the ventral part of it in front of the attachment of the palatines. The preaxial end of the zygoma is less dorso-ventrally expanded. The preaxial margin of the palatine is slightly less, and its ventral margin rather more, concave. Tbe postero-inferior angle is larger and more prominent, while instead of the more or less long postaxial process (pp), which in P. erithacus projects dorsad and postaxiad from the summit of tbe postaxial margin of tbe palatine, there is an exceedingly small one which does not project as much as does the ventral boundary of the postaxial concavity of the bone. The external surface of the palatine is also more concave dorso-ventrally, especially in its hinder half. Of the dorsal margin of tbe palatine the part joining the basis cranii is about as long, relatively, as in P. erithacus, but tbe part of that margin postaxial to that junction develops two processes towards its postaxial termination. The orbit is almost bounded infero-externally by bone, the lachrymal extending postaxiad to within a short distance of the sphenotic process (sph). Posteriorly, however, the orbit is less encircled by bone at its outer margin, for the postorbital process (po) is very much shorter, not projecting at all downwards, and relatively not so much outwards as in P. erithacus. The sphenotic process is also relatively somewhat shorter and notably different in shape, and it does not descend, as in P. erithacus, almost to the dorsal margin of the zygoma. In the latter species it projects forwards and downwards and also a little outwards. It is flattened dorsally and externally, and is longitudinally channelled on its ventral surface, the inner margin of that channel being prolonged into a short pointed process, 24* |
