No. 433.] CERTAIN GROUPS OF BIRDS. 



53 



The late T. J. Parker, who makes three subfamilies and five 

 genera of the family Dinornithidae (Trans. Zoo/. Soc, London, 

 October, 1895, pp. 417 et seq.), has, among other extensive 

 osteological comparisons of these birds, pointed out the follow- 

 ing facts, which he tabulates thus : 



The Skull in the Dinormthidce. — OQZ^zX plane vertical or 

 very slightly inclined backwards or forwards ; occipital condyle 

 pedunculate ; occipital crest variable. Length of cranial roof 

 from two to two and a half times length of basis cranii. 



Mammillar tuberosities usually prominent ; basitemporal plat- 

 form always well defined and separated from occipital condyle 

 by a deep precondylar fossa. 



Width at paroccipital processes from less than one and a 

 half to more than twice length of basis cranii. 



Width at squamosals from about one and three-quarters to 

 one and a half times length of basis cranii. 



Height of cranium about one and a quarter times length of 



Temporal fossa extends mesiad, to a greater or less extent, 

 on to parietal region ; distance between temporal ridges varies 

 from about width of cranium at temporal fossae to half that 

 width. Zygomatic process short, pointed, and nearly parallel 

 to median plane; auditory region of skull produced into a 

 strong squamosal prominence. 



Width of orbit about half width of cranium at paroccipital 

 processes, and almost invariably less than length of basis 

 cranii ; interorbital septum absent or greatly reduced ; a broad 

 supraorbital ledge, produced behind into a strong, broad, post- 

 orbital process. 



Lacrymal ankylosed with frontal, forming preorbital process ; 

 no orbital process ; a descending process ankylosed with outer 

 border of antorbital, and notched or perforated for lacrymal 

 duct. Mesethmoid produced into paired horizontal triangular 

 processes. Antorbital well ossified ; ankylosed to descending 

 process of lacrymal; perforated dorsally by a supraorbital 

 fenestra of variable size. 



Nasal either has a slender maxillary process, or there is a 

 distinct maxillo-nasal bone; meets its fellow of the opposite 



