No. 44<'>-] RECLASSIFICATION OF IH F RFrilLIA [ i c; 



the Choristoclera, by McGreg-or on the Parasiichia, will furtlu-i- 

 ehicidate the still numerous and per])le.\in<;- questions .it plu 

 logeny. 



Origin of /irv.s-.— The birds probably ori<;-inatr(l tioni ;i 

 group of Diaptosauria identical with or closely rehitcul to that 

 which gave rise to the Dinosauria. It is not true that birds 

 have descended from dinosaurs, but there is very strong evi- 

 dence that birds and dinosaurs are descended from a common 

 stock. 



Origin of JA?;;/;;wA-.— There is no t|ucslioii that the mam- 

 mals are affiliated with the subclass Synapsida ratliei- than with 

 the Diapsida ; both in skull and shoulder girdle structure and in 

 the phalangeal formula they are Synapsidan. 



As to their nearer relationships they appear to be rather with 

 the superorder Anomodontia and with the order Cynodontia or 

 Theriodontia. The divergence of the mammal stem from these 

 typical reptiles will probably be found to have occurred in the 

 Permian or Lower Trias of South Africa. In fad Broom has 

 recently described what he believes to be a mammal jaw, 

 Karoomys, from the Karoo Beds of South Africa. 



