OCR Text |
Show 1899.] CRANIAL OSTEOLOGY OF THE PARROTS. 43 well-marked notch on the lower margin of the squamosal process at the place of the quadrate articulation, much as in Stringops. The auditory meatus is very narrow and crescentic in form ; the space between it and the descending occipital ridge is very wide ; the basitemporal region is nearly on a level with the occipital condyle; the paroccipital process is blunt (except in Pyrrhulopsis) ; the orbital ring is incomplete and the postfrontal process almost obsolete or represented only by a vertical ridge; the nostril is large, the interorbital fenestra is moderately so, the mandibular fenestra is extremely small or obsolete. While Melopsittacus appears to differ most markedly from the above in its complete orbital ring, with its bridge, as in the Cockatoos, across the temporal fossa, yet at the same time it possesses an extremely well-marked notch at the base of the squamosal and a deeply-excavated surface between this and the suprameatal tubercle ; it agrees in all the other characters mentioned above with the Platycercince, of which I have no doubt it is a real, though a somewhat aberrant, member. The case of Calopsittacus is a little more difficult. While in the Cockatoos the auditory meatus reaches backward to the descending occipital ridge, in Calopsittacus as in Melopsittacus there is a wide interspace between. The auditory meatus is proportionately narrower than in the Cockatoos. The temporal fossa, though bridged by bone as in the Cockatoos, is much smaller and narrower than in them. There is a very distinct notch at the base of the squamosal and a well-marked surface between it and the suprameatal process, though this is not nearly so conspicuous a feature as in the Platycercince. The nostrils are very large and near together as in Melopsittacus, and are very different from the small, round, and distant nostrils of the Cockatoos. On the whole I should say that, so far as cranial osteology goes, the position of Calopsittacus is an open question, and that it is by no means impossible that it may really deserve to be grouped somewhere near Nymphicus and Melopisittacus. While the facts suggest at least the possibility of a closer affinity than that usually recognized between the two Australian groups of Cacatuince and Platycercince, this larger question must also remain for the meantime in uncertainty. The true Lories form a natural group, and their place is, I believe, not far from the Platycercince. The auditory meatus is constricted, its posterior border is crescentic and widely separated from the occipital ridge. The orbit is incomplete and the postfrontal process almost obsolete or (as in Eos) narrow and vertical. The squamosal process is more or less distinctly notched at its base, more in Lorius, much less in Trichoglossus, and the well-marked suprameatal process overhangs a surface of bone, to which ascends, as in Aprosmictus &c, the bar which separates the auditory cavity from the region of the quadrate articulation. The excavated region of the base of the squamosal is not nearly so complete as in the Platycercince, but yet it is more like to them than to any other family of Parrots. The three genera grouped by Salvadori as Psittacince, namely |