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Show 1899.] CRANIAL OSTEOLOGY OF THE PARROTS. 29 antero-posteriorly, while in the others, as in A. hyacinthinus, that of each side converges inwards : in the same species the angle is somewhat less truncated than in the others, and the facet for the insertion of the depressor muscle smaller, more rounded, and not ascending, as in the rest, on the posterior margin of the bone. THE CONURES. Excluding the Macaws, I have examined of the other Conuridse, Conurus, Pyrrhura, Myopsittacus, and Brotogerys. The skulls of the first, differ from those of the last two materially. In Conurus I have found the orbital ring complete in 0. leucotis, but incomplete in G. ceruginosus (fig. 21) and G. hcemorrhous: in both of the latter, however, the imperfection is but slight, the prefrontal process running backwards nearly to contact with the postfrontal. The squamosal process is somewhat stout, and curves forward iu the direction of the orbital ring ; its lower border forms a marked notch over the region of the quadrate articulation. The auditory meatus is considerably wider in C. hcemorrhous than iu the other Fie. 21. Conurus ceruginosus. two species, and the upper and lower notches are accordingly better marked in the latter. The inner head of the quadrate is of considerable size ; the anterior process is very slender ; the posterior angle of the bone is reduced, and the articular surface runs up abruptly to end in a prominence on a level with the base of the shaft, making the outer surface of the bone appear narrower than usual; but this last character is much less marked in C. hcemorrhous than in the others. The paroccipital wings and basitemporal ridges are well developed. The supra-occipital is markedly tumid in the region of the middle lobe of the cerebellum. The mandible is extremely short and broad, and its fontanelles are obsolete. The descending processes from the hinder border of the maxilla are very well developed in G. hcemorrhous, but not so in the other two species. In Pyrrhura hcematotis the orbital ring is complete, as in C. leucotis, and the whole skull differs little from the latter species, except that a mandibular fontanelle is present and the interorbital vacuity is unusually large and rounded or less produced posteriorly. In Brotogerys and Myopsittacus the orbit is incomplete, and the |