PROTOZOA : INFUSORIA. >;■] 



Affinities of the Infusoria. — Though generally placed 

 amongst the Protozoa, of which they form the highest division, 

 the position of the Infusoria cannot be looked upon as defi- 

 nitely settled. There is a growing opinion amongst competent 

 authorities that the Infusoria should be entirely removed from 

 the Protozoa, and that they should be placed amongst the An- 

 nuloida, having their nearest allies in the Turbellarian Worms. 

 If this change be carried out, the Infusoria and Rotifera, which 

 older naturalists grouped together, and which modern ob- 

 servers have placed widely apart, will be again brought nearly 

 together. If the sponges also should be removed from the 

 Protozoa, as is maintained by some modern observers, then 

 the entire sub-kingdom of,, the Protozoa would' contain only 

 the Gregarinida, Amosbea, Foraminifera, and Radiolaria. At 

 present, however, there certainly do not appear to be suffi- 

 ciently decisive grounds for such a step ; and the affinities of 

 the Spongida are certainly more intimate with the typical 

 Rhizopods than with the Ccelenterata. 



