PHTLOGENY OF THE PAL.EOGNATH.E AND KEOGNATH-E. 



179 



In Bromaus the outer fork of the >-shaped notch of the upper limb is s^'eatly 

 developed, forming a long, backwardly directed, spine-like supra-orbital process 

 (PI XLII fi- 2). The inferior limb is notched below the lachrymal ioramen. 

 In I) novwhlllandm the inner fork of this notch is short and confluent with the 

 free ed-e of the ventral border of the antorbital plate. The outer fork is produced 

 downwards far beyond this, and rests upon the quadrato-j ugal bar. In D. irroratns 

 and B ater the outer and inner forks of the prong are subequal, and do not quite 

 reach the level of the ventral border of the antorbital plate, which is continued 

 downwards by means of a slender column on to the maxiUo-palatal process, where it 



expands. ,. , • ^- i 



In Struthio (PI. XLII. fig. 3) the outer fork of the upper hmb is comparatively 

 short and blunt, and projects more laterally than in the above mentioned, further- 

 more it differs in that it is joined by a series of large bony scales l>ing between its 

 posterior extremity and the supra-orbital ledge of the frontal, recalling the supra- 

 orbital chain of bones in the Tinamou. Late in life the scales fuse with the laciuymal 

 in front and the frontal beliind, thus enclosing a large supra-orbital foramen. The 

 lower limb of the lachrymal takes the form of a slender backwardly curved rod, whose 

 free end is curved sharply outwards to join the inner border of the quadrato-j ugal bar. 

 To the inner side of this outwardly directed free end is attached a larger ossiculum 

 palatinnvi, which in the adult fuses witli the lachrymal on the one hand, and the 

 antorbital plate on the other. Below the ventral border of its inner end comes m 

 contact with the palatine. 



jEmjornis and Dinomis have the lachrymal so completely fused with the frontal 

 and antorbital as to be with difficulty distinguishable. The upper limb in both has 

 completely merged into the supra-orbital ledge. The lower in Binormthda^ is much 

 flattened antero-posteriorly. The lachrymal foramen is imperfect, its outer bar being 

 wanting. In some, e. g. Ammalopteryw, it is perfect. Its ventral extremity is squarely 

 truncate and articulates with the maxillo-jugal bar. 



In the only yEinjornis skulls I have been enabled to examine, tliis lower limb has 



been broken away. . 



In both these groups the anterior border of the lachrymal rests against a well- 

 marked, spine-like, maxillary nasal process. 



In Apferyx the lachrymal is described by Parker [71], from young specimens, as "a 

 small irre-ular bone consisting of a shell-like central portion applied to the surface of 

 the aliethmoid, and of an ascending portion which articulates with the descending 

 process of the nasal. It is perforated obliquely by the lachrymal foramen." In the 

 adult it is completely fused with the aliethmoid. Its anterior border is often traceable 

 as a thin suture between it and the maxillary process of the nasals. 



In the Crypturi the lachrymal is indistinguishably fused with the nasal, and forms 

 therewitli a prominent outstanding process bounding the orbit in front. There are no 

 backwardly projecting spines. The ventral limb fuses with the antorbital plate. 



