]^46 Walter Rothschild. 



Order I . Struthiornithes consisting of the genera 



Struthio and probably Macrornis. 

 Order II Rheornithes consisting of the genus Rhea 



and the later discovered Mesemhriomis. 

 Order III Hippalectryornithes with the genera Dro- 



maius, Casuarius, Dromornis, Genyornis, 



Megalornis, and Bypselornis. 

 Order IV Aepyornithes with the genera Aepyornis, 



Müller omis, f Biatryma, ? Dasornis and 



Eremopezus. 

 Order V Alectorornithes including the families Aptery- 



gidae, Dinornithidae and Crypturidae. 

 This arrangement has been adopted, with great modifications, 

 as a basis of classification by Mr. W. P. Pycraft in the Mono- 

 graph of Cassowaries by myself and him, published in the Trans- 

 actions of the Zoological Society of London. Mr. Pycraft divides 

 the Class Aves into 3 divisions viz. 



1. Archornithes containing Archaeopteryx. 



2. Palaeognathae containing the socalled Bafitae and the Crypturi. 



3. Neognathae containing the rest of the birds knov\^n. 



This classification Avill I believe prove to be the most natural 

 one and eventually everyone will adopt it. I have not made use 

 of the term Palaeognathae everywhere in this paper, simply 

 because I am only dealing with a portion of the group and the 

 term Ratitae, hoAvever misleading in sense and application, as 

 originallv used, serves to more quickly indicate the section of the 

 Palaeognathae I am dealing with. For the purposes of this lecture 

 it appears advisable to treat the fossil forms from the Jurassic 

 down to the Miocene as one group under the title of Heterornithes ; 

 this would then work out as follows as regards Dr. Gadow's 

 Section 2 of his Division L 



2. Heterornithes. 



South American . Mesemhriomis. 



North American . Dyatrima, Lao pteryx a.nà Baromis. 



European Bemiornis, Dasornis, Gastornis, Macrornis 



and Megalomis. ~ 

 North African . . Eremopezus and B sani m omis. 



The term Ratitae is misleading because of its application. 

 It was applied to the near relatives of the Ostrich and means the 

 birds with a raft i. e. raft-like sternum. But there are many birds 

 in no sort of way related to the Ostrich Avhich, having lost the 

 power of flight, have evolved a more or less complete raft-like 

 sternum, though otherwise retaining their carinate character. 



Among the Bsittacidae we have Stringops, the Steganopodes 

 have produced Bhalacrocorax harrisii and there are a number of 

 such forms among living and extinct Ballidae. 



