Present disti ibution of the so called Ratitae. 147 



It is most necessary, therefore, when considering the relation- 

 ship of the heterogeneous assemblage of forms which I have for 

 convenience of reference united in this lecture under the heads 

 Heterornithes and Ratitae, to remember that the loss of flight 

 and conscciucnt acquisition of a raft-like sternum are no proof 

 of any very close relationship. Mr. P y craft takes as the 

 salient character in his classification the Dromaeognathous 

 palate, which is present in his Palaeognathae and absent in his 

 Neognathae, and further suggests that the latter have branched 

 oif from the ancestor or ancestors of the stock which gave rise 

 to the Rheo-Dinornithine type of palate and pelvis, i. e. the 

 ancestor of Mesenihrionus. 



I will begin with the more ancient strata and discuss the 

 Heterornithes as the immediate fore-runners of the type of large 

 flightless birds which I am treating of in this paper, under the 

 title of Ratitae. 



As far as I have been able to discover only one bird is known 

 from the Jurassic formation which can be associated with these 

 ancestors of the Ostrich-like birds. All the rest belong to the 

 tertiary formations having been found in the various Eocene strata. 



Beginning with the regions where fewest have been found 

 the following are the species and genera included in the 

 Heterornithes. 



North Africa. 



Eocene. 



Eremopezufi eocaenus Andr Fayoum. 



Psaninior?iis rotJischiJdi Andr South Algerian Sahara. 



South America. 



Miocene. 

 Mcsernhriornis studeri Mor. & Merc. . . . Argentina. 

 Mesemhriornis quatrefagesi Mor. & Merc. „ 



Meseinbriornis milne-edwardsi Mor. & Merc. „ 



North America. 



Jurassic. 

 Lauptevyx prisca Marsh Wyoming. 



Eocene. 



Barornis regens Marsh New Jersey. 



Diatri/ma gigantea Cope New Mexico. 



Europe. 



Eocene. 



Macroniis tanaupus Seeley Hordwell, England. 



Megalornis emuinus (Bowerbank) Isle of Sheppey, Engl. 



Dasornis londiiiensis Owen „ 



,, ,, Lower Eocene. 



i 0* 



