PHYLOGENT OF THE PAL^OGNATH^ AND NEOGiNATH^. 263 



validity of my conclusions rather than his, for those who know his monographs on the 

 development of Apteryx and the skull of the Dinornithidce will agree that they are 

 monuments which mark an epoch in the history of this subject. In his work on the 

 skull of the Binornithidce he wrote : " The marked differences between the Moas and 



Kiwis are certainly for the most part adaptive The real affinities underlying 



these differences are, however, shown by the striking similarity of the bones of the 

 palate in the two forms." 



The skull of Casuarius, it may be remarked here, differs in no essential respect from 

 that of Dromceus. In whatsoever it differs from Dromceus point to specialization, as, 

 for instance, the development of the casque upon the mesethmoid (p. 199, PI. XLIV. 

 fig. 3) and the small quadrato-jugal fossa. 



The skull of Dromceus, it would seem, must be regarded as the most generalized of 

 living birds, at least in so far as the bones of the palate are concerned. 



Struthio somewhat nearly approaches Dromceus in the arrangement of these bones. 

 Rhea, the Tinamous, the Binornithidce, and probably the yEpyornithidce agree more 

 closely one with another than with Dromceus. 



Apteryx differs from all in the direction of increased complexity of these parts. 

 We have now Struthio and Dromceus with Casuarius opposed to Rhea, Dinornithidce, 

 and Crypturi, and possibly yEpyornis. These last we may further subdivide by 

 means of the pelvis. This will separate Rhea from the remaining forms; inasmuch 

 as in Rhea the pelvis is long and narrow, with the post-acetabular ilia meeting in the 

 middle line, as in Apteryx. 



In the Dinornithidce, yEpyornis, and the Tinamous the post-acetabular ilia are 

 separated by the long transverse processes of the synsacrum. 



It may seem that this character of the pelvis is a somewhat artificial one, but 

 reflection will show, I think, that it is probably not so. It does not seem to belong 

 to the category of adaptive characters, since Rhea and Apteryx in the general confor- 

 mation of the pelvis agree, though their habits are very different, and both bear some 

 similarity to that of Struthio — similar in so far as the great length and transverse 

 width are concerned. In the Tinamidce, Dinornithidce, and yEpyornis the pelvis owes 

 its great breadth to (1) elongated transverse processes, and (2) the broad dorsal plane 

 of the post-acetabular ilium. 



The pelvis of Struthio bears an undoubted resemblance to the Dinornithine form, 

 inasmuch as, like Dinornis or yEpyornis, the transverse processes bear the post- 

 acetabular ilia away from all contact with the neural spines of the synsacrum. 



Fiirbringer's view with regard to the Dromceidce is not exactly in harmony with 

 the views adopted here, but it lends some support thereto nevertheless. He says 



Dromceus and Casuarius "bilden zwei sehr nahe verwandte Familien welche 



etwas hoher als die Struthionidce, aber tiefer als die Rheidce stehen und im Ubrigen 



sowohl von den anderen Ratiten als von den Carinaten eine entfernte 



2o 2 



