204 MR. W. P. PYCRAFT ON THE MORPHOLOGY AND 



for the lachrymal duct is very large. This lachrymo-nasal process stops short of the 

 quadrato-jugal bar and is connected therewith by a large subquadrate ossiculum 

 lachrymo-palatinum. Internally the last eventually fuses with the antorbital plate. 



In Struthio the lachrymal resembles that of Bhea. Its supra-orbital process is, 

 however, relatively shorter and thicker. In two nearly adult skulls (one of which is 

 from the collection of the Hon. Walter Rothschild) this orbital process supports one 

 end of a chain of irregularly shaped ossicles which is continued backwards along the 

 frontal as far as the post-orbital process. Normally this chain of ossicles is so completely 

 fused as to be indistinguishable from the frontals on the one hand, and the lachrymal 

 on the other. There is a large supra-orbital fenestra bounded in front by the lachrymal 

 and behind by the frontal ; externally by a portion of this chain of supra-orbitals. 



The lachrymo-nasal process is continued downwards as a sigmoidally curved rod to 

 terminate on the inner side of the quadrato-jugal bar. On the inner side of this 

 extremity of the lachrymal there lies a subcylindrical ossiculum lachrymo-palatinum 

 articulating mesially, in very old specimens, with the antorbital plate. The lachrymal 

 foramen is represented only by a deep notch. 



In Apteryx the lachrymal is vestigial, and takes the form of a small roughly triangular 

 plate of bone closely applied to the outer surface of the aliethmoid and the maxillary 

 process of the nasal. It is perforated by the lachrymal foramen. 



The premaxilla, maxilla, jugal, quadrato-jugal, vomer, palatine, and pterygoid differ 

 in no important respects from that of the adults already described (p. 187). 



The vomer, pterygoid, and palatine of Apteryx demand, however, a further examina- 

 tion, as these in the adult ai - e too completely fused with the neighbouring bones to 

 render it possible to make out their boundaries. 



The pterygoid is bifid cephalad, being divided into two moderately long, pointed and 

 widely separated prongs. The inner prong, which constitutes the main body of the 

 bone, is deeply grooved along its mesial border, producing two shelf-like projections 

 one above the other: these converge near the tip of the prong to form a slender pointed 

 style resting in a groove on the outer border of the posterior extremity of the vomer as in 

 other Palwognathce, and as in the hemipterygoid of Neognatlm, e. g. Impennes, Colymbi. 

 The outer limb is closely applied to the ventral and external aspect of the extreme 

 hinder end of the maxillo-palatine process, extending as far forwards as the point from 

 which the maxillary portion of the quadrato-jugal bar is given off. In the cleft between 

 the outer and inner limbs the palatine is interposed, as will be seen presently. 



The palatine is short and broad, with a slightly bifid free extremity. It can only be 

 seen in its entirety from above. It is closely applied, throughout its entire length, to 

 a b&ckwardly projecting plate from the maxillo-palatine process. This it entirely 

 conceals from above. Its proximal extremity sends off, upward and inward, a flange- 

 like plate to articulate with, and underlie, the extreme hinder end of the vomer. 

 Thus this last has its right and left limbs sandwiched, on either side, between the 



