SnuFr.i.DT : Ostf.olocv oi- iiik 1 Ikrodioxes. 243 



The small foramen for the exit of the first pair of nerves is a short 

 and rather broadish slit, and the nerve passes forwards in a very well 

 defined, open groove, which leads directly into a circular foramen in 

 the supero-mesial angle of the thickened pars plana of the ethmoid. 

 The " foramen rotundum " is just of a sufficient size to pass its nerve, 

 as is also the case with the lesser opening to its outer side. Still further 

 CKternally we note in plain view, the foramen ovale. It is likewise 

 circular in outline, and nearly equal in size to the foramen rotundum. 

 A zygoma is short, very straight, and slender. Proximally, it makes the 

 usual articulation with the quadrate, while distally, the maxillary por- 

 tion completely fuses with the very broad nasal and the premaxillary. 

 This latter end of the zygomatic arch is found in a much higher plane 

 than the quadrato-jugal extremity when the skull is in the horizontal 

 position. At its externo-inferior angle the pars plana develops an out- 

 standing thin plate-like process that fails to quite come in contact with 

 the lacrymal. This latter bone is not large, and is twisted upon itself, 

 so that its descending plate faces forwards and backwards ; while from 

 its lower external angle a little tip is produced, which through the 

 medium of a short rod-like and free os iiiiciiiattiin, is extended so as 

 to reach the maxillary bone below. 



In front of these three last-named, and branded anteriorly by the 

 free, sharp, convex margin of the nasal, we are to observe a large, 

 subcircular vacuity that looks into the rhinal chamber. This last is 

 much filled in by the very extensive and fused osseous mass, made up 

 chiefiy of the swollen and spongy inaxillfl-palatiiics. The anterior 

 wall of the brain case is more than usually thick and dense, and is un- 

 perforated in any part of its extent by foramina. Posteriorly, the 

 cranium of A'aja is more than commonly rounded and smooth ; the 

 occipital ridge being but feebly pronounced, and the supraoccipital 

 prominence not very decidedly marked. On either side of this the 

 bone is very thin, but foramina are not seen there in thoroughly ma- 

 tured birds, as they are in Plegadis and Guara. Foramen magnum is 

 inclined to be large, and is nearly circular in outline. Its plane 

 makes an angle of about 45° with the base of the cranium or more. 

 The condyle, of no great size, is at the same time somewhat jutting. 

 At the base of the cranium the outstanding paroccipital processes are 

 conspicuous, and the small basitemi)oral area is tilted upwards, so that 

 its anterior apex occupies a much higher plane than its base posteriorly. 

 The thickened sphenoidal rostrum is inclined to be triangular for its 



