134 MB. W. P. PYCKAFT ON THE MORPHOLOGY AND 



The maxillary, which is confluent for about half of its length with the palatine 

 process, is styliform, and terminates in the anterior region of the antorbital fossa. 



The palatine process is of great size, extending beyond the maxillary process, and 

 terminating at, or falling but little short of, the anterior border of the posterior nares. 

 I this it agrees with Dromasus. 



Struthio differs from all the other Ratitce in the absence of a palatine process, and the 

 consequent enormous size of the palatine foramen. 



The whole premaxilla has a unique triradiate form ; the radii are of great length, 

 so that the body of the bone is reduced to the smallest possible dimensions. 



The nasal process is broad and flattened, tapering somewhat abruptly posteriorly. 



The maxillary processes are long and styliform, terminating at the level of the 

 anterior region of the orbit. 



In Cryphiri the form of the premaxilla is precisely similar to that of Bhea. The 

 free end of the palatine process is brought to the level of the anterior border of the 

 posterior nares, and interlocks with the distal end of the palatine. In this last point 

 it differs from Rhea. The palatine foramen, as in Rhea, is long and narrow. 



Apteryx is the most abnormal of all the Palaeognathm. The whole beak is 

 produced forwards into an elongated probe, curved slightly downwards, in the tip of 

 which the external nostrils lie. 



In the adult skull the fusion of the separate elements, not only of this region of the 

 beak alone, but of the skull generally, is so complete, that it is impossible to 

 make out their boundaries. 



The body of the premaxilla is reduced to its smallest possible limits, being com- 

 posed only by the confluent end of the rod-like nasal process, and of the combined 

 maxillary and palatine processes, which for this reason are but delicate rods. 



The nasal process takes the form of a long slender rod, grooved ventrally and 

 running backwards to the mesethmoid. Its posterior region rests upon the elongated 

 nasal bones. 



The maxillary and palatine processes are fused throughout the greater part of their 

 length, and form elongated flattened rods, divided in the middle line by a narrow groove 

 representing the palatine foramen. Posteriorly there is given off a short splint-like 

 palatine spur, representing the palatine process. The extremest limit of this falls 

 considerably short of the anterior end of the antorbital fossa. 



The maxillary process can be traced backwards splint-wise as far as the level of the 

 foot of the lachrymal. Thus the maxillary processes are of about equal length. 



The nasal, and nasal process of the premaxilla above, and the maxillary process of 

 the premaxilla below, serve to form a long narrow groove leading forwards into the 

 anterior nasal fossa, this last having shifted forwards to the extreme end of the beak. 

 This nasal furrow bears a strong resemblance to that of the Ibises, the difference beino- 

 that the nasal fossa lies behind instead of in front of the groove, as in Apteryx. It 

 seems to suggest that the shifting forward of the nasal aperture has followed the course 



