1899.] CRANIAL OSTEOLOGY OF THE PARROTS. H 



is then said to be continued into two lateral processes, and it arises, 

 at any rate, very near the meeting-place of the frontal and squa- 

 mosal, which may very possibly both be found to contribute to its 

 formation. 



Separated from this postfrontal process by the temporal groove 

 or fossa is the zygomatic process of the squamosal, which it is 

 more convenient to call the squamosal process ; this, in the Grey 

 Parrot, is the larger and longer of the two. It is seen to be 

 slightly indented below near its apparent origin from the skull, 

 and to jut downwards behind the slight indentation (much more 

 conspicuous in certain other forms) which marks the place where 

 the glenoid cavity for the outer head of the quadrate is excavated 

 below. A slight tubercle projects outwards from, or rather behind, 

 the base of the zygoma, behind the glenoid indentation, and is the 

 suprameatal process of Mivart \l. c.) ; between it and the glenoid 

 notch is a small grooved area which in some genera becomes con- 

 spicuous. I shall speak of it as the suprameatal area. From the 

 anterior lower margin of the orbit there runs, curving backwards, 

 and crossed near its origin by a well-marked horizontal groove, the 

 preorbital or suborbital process, which represents the posterior 

 process of the so-called lachrymal bone. We shall find that the 

 relative size of these processes, their fusion or want of fusion to 

 complete or leave incomplete the orbital ring, and the completion of 

 the orbital ring by union of the lachrymal in some cases with the 

 postfrontal, in some also with the squamosal process, furnish us 

 with several important distinctive characters. 



While it is not the object of this paper to deal with the higher 

 morphological questions, I may point out that the so-called lachrymal 

 bone is (at least in my opinion), obviously no lachrymal, but a 

 prefrontal (with which in some cases an inconspicuous lachrymal 

 may be conjoined), as nearly as possible identical in its characters 

 and relations with the prefrontal of the Lizards. The bone in a 

 lizard (e. g. Iguana) comes into relation with the frontal, nasal, 

 lachrymal, superior maxillary, jugal, and palatine bones. Its dorsal 

 portion, precisely comparable in most birds to its dorsal ramus in 

 the Lizards, is in relation with the nasal and frontal. Though it 

 does not in any one bird exhibit all the other relations of the 

 lacertilian bone, yet we may discover them severally in one bird or 

 another : in the Snowy Owl, in Balceniceps, and in Podargus it meets 

 or unites with the maxilla ; it comes into relation with the palatine 

 in Struthio and Apteryx ; it meets more or less intimately with the 

 jugal in the Penguins, Petrels, Cormorants, Gypogeranus, and 

 others ; while in the Eaven and many other Passerines, the 

 Penguins, the Guillemots, the Curlew, the Toucan, the Parrots, 

 and many more, it comes into relation with, or fuses with, the 

 ethmoid region, a relation that we cannot seek in the bony skull of 

 the Lacertilia. In Ducks, Geese, and Swans its inferior ramus 

 inclines backwards in the direction of the postfrontal process (the 

 squamosal or zygomatic process being here absent or rudimentarv), 

 as it does in the Parrots, and it is said (though I have not actually 



