1907.] TO THE OSTEOLOGY OP BIRDS. 357 



The lachrymal, which is attached, as a rule, to the outer mai-gin 

 of the antorbital plate, demands some notice. Unfortunately, in 

 a very large proportion of prepared skeletons of birds this is 

 absent, often because of its reduced size which causes it to be 

 overlooked by the macerator. And thus it becomes impossible to 

 say, when this ossicle is missing, whether it has been lost during 

 maceration or suppressed. That suppression has taken place in 

 not a few instances is almost certain, inasmvich as in skeletons in 

 this collection it may be found reduced to the vanishing point. 



In the Families which form the subject of this paper, the 

 lachrymal is least reduced in Graucalus among the Oampo- 

 phagidpe, and in Laniarius among the Laniidse. In Graucalus it 

 is roughly ID-shaped, and attached to the anterior face of the 

 antorbital plate ; the free ends of this horseshoe curve are 

 directed outwards, the lower limb projecting beyond the outer 

 border of the plate, and resting on the quadrato-jugal bar. It is 

 formed of highly pneumatic bony tissue and has a conspicuously 

 inflated appearance. In Laniarius this ossicle is almost rod- 

 shaped, and has its inferioi', free end twisted outwards, con- 

 siderably swollen, and resting on the quadrato-jugal bar. The 

 main shaft is attached to the anterior face of the antoi-bital plate, 

 while its upper end is wedged in between the nasal bone and the 

 antorbital plate. Gymnorhina agrees veiy nearly with Laniarius 

 in this respect, differing chiefly in that the inferior end of the 

 ossicle rests in a facet on the quadrato-jugal bar. In Artamus 

 and Artamia it is greatly i^educed — in the former, for example, 

 being represented only by a very delicate rod, with a cordiform 

 inferior extremity which does not reach the quadrato-jugal bar, but 

 which projects slightly beyond the level of the antoi'bital plate. 

 Prionops in this matter resembles Artamus, except that the rod is 

 somewhat thicker and not markedly inflated at its inferior end. 

 In Euryceros it has the form of a sigmoidally curved rod attached 

 to the face of the antorbital plate, as in the preceding cases, and 

 extending downwards to articulate with a tumid prominence on 

 the quadrato-jugal bar. In the Tyrannidfe it is attached, not to 

 the anterior face, but to the outer, free edge of the antorbital 

 plate, and extends upwards to the level of the nasal, and down- 

 wards to the quadrato-jugal bar. In shape it may be described 

 as spatulate, the blade being flattened along its mesial border 

 where it comes into contact with the antorbital plate ; while the 

 handle has a strong outward curvature. Finally, in Phytotoma 

 all that is left of this ossicle is a minute spicule attached to the 

 outer edge of the antorbital plate. In no case is an orbital 

 process developed ; and only in Laniarius is the shaft perforated 

 by a conspicuous pneumatic foramen. 



The ossification of the nasal septum and of the walls of the 

 olfactoiy chamber gives this region of the skull, in the groups now 

 under consideration, an unusual importance. 



In the Tyrannidte, this septum, in its simplest form, as in 

 Pitangus, extends from the cranio-facial fissure to the anterior 

 end of the narial orifice, and has a knife-like free edge dividing 



