264 MR. W. P. PYCRAFT ON THE MOEPHOLOGY AND 



Stellung einnehmen,' 1 and adds: " Ihre Vorgeschichte kommt mir am meisten dunkel 



vor. 



By this time the tendency of the foregoing will no doubt have revealed itself. Its 

 intention is to suggest that Dromceus and Casuarius — the Dromceidce — are to be 

 regarded as the most primitive of the Palceognathce ; and that the StruthionidcB are 

 most probably the nearest approach thereto, for, in spite of the great specialization 

 which they have undergone, they undoubtedly retain many archaic characters. 



The Bheidce, Linomithidce, JEypomithidoe, and CryptuH are all probably more 

 nearly related one to another than to the Dromceidce. The Apterygidce are the most 

 aberrant of all, but have affinities with the Linomithidce. 



This implies that the Palceognathce are to be regarded as polyphyletic — probably 

 triphyletic. An attempt to express this relationship is given in the diagram on 

 p. 265. 



I propose to discuss the details of this " tree " in so far as concerns the Neognathce 

 elsewhere. Of the Palceognathce I need only say I recognize 7 Orders, viz. : — 



Casuarii. 



Struthiones. 



Rhese. 



Crypturi. 



Dinornithes. 



JEpyornithes. 



Apteryges. 



Their relation to the other members of the Class may be expressed as follows: — 



Class AVES. 



Subclass I. Arch^ornithes. 

 „ II. Neornithes. 



Grade A. Palceognathce. 

 „ B. Neognathce. 



It would have been helpful here to discuss the further evolution of this group to its 

 final end in the various genera and species, but this is unfortunately impossible in 

 the present contribution owing to lack of material. The diagram will give a slight 

 indication of the writer's views on this subject. 



