THE OPALINID CILIATE INFUSOKIANS. 



315 



was in existence before Australia separated from Asia-Malaysia and 

 so was pre-Cretaceous, apparently Jurassic, in origin (figs. 234,233). 

 They spread to Europe either during the Cretaceous (fig. 234) or 

 in the late Tertiary (fig. 237), and to Africa in the late Tertiary 



(fia 237) Their absence from South America indicates that they 

 did not arise in Equatoria (fig. 232). Our scant records from south- 

 ern Asia do not show members of this group present south of the 

 Himalaya Mountains. Probably the spreading from the Australia- 



