DISCOVERIES IN AVIAN PALAEONTOLOGY. 411 



osteology of the group. He has had opportunities of exa- 

 mining a very large number of skulls, some of which are 

 those of young individuals in which the sutures are still 

 open, and has, therefore, been able to give a very detailed 

 account of the structure of this, the most important portion 

 of the skeleton. Moreover, he has given a scheme of 

 classification of the group, founded exclusively on cranial 

 characters ; the importance of this is obvious to any one 

 acquainted with the terrible state of confusion into which, for 

 various reasons, the nomenclature of the Moas has got. Five 

 genera are recognised, and it would be very advantageous 

 if these could finally be adopted, particularly as they agree 

 in the main with those accepted by Lydekker in his cata- 

 logue of the British Museum collection, which, containing 

 as it does the types of most of the species, must be the 

 final court of appeal in most questions relating to the 

 nomenclature of the family. Professor Parker has added 

 a very detailed comparison of the Dinornithine skull with 

 those of the other Struthious birds, and arrives at some inter- 

 esting results as to the relationships existing between the 

 various types. He considers that the Ratitae are a poly- 

 phyletic group, Rhea and Struthio having originated inde- 

 pendently of one another and of the forms inhabiting 

 Australia and New Zealand. The latter arose from a 

 common stock which early divided into two branches, 

 the one giving rise to the Australian genera, Dromczus 

 and Casnarius, the other to the New Zealand forms. The 

 latter again divided into two branches, one leading to the 

 ApterygidcB, the other to the Dinornithidce. Of this family 

 Dinoruis and Emeus are regarded as having diverged most 

 widely from the ancestral type, which is probably most 

 nearly represented by Mesopteryx. This view differs from 

 that of Burckhardt mainly in the refusal to admit a common 

 ancestry of Struthio and the Casuariidae, otherwise it is in 

 general agreement with it, and is supported by the geo- 

 graphical distribution of the various forms. Unfortunately 

 palaeontology throws little or no light on the history of the 

 Struthious birds, no fossil form that can be referred to that 

 group with certainty being known from strata older than 



