PEOTOZOA. 



11 



sule) and Entolithia (skeleton more or less within the capsule). 

 Mivart proposes to divide these into seven " primary groups "- 

 Discida, Flagellifera, Entosphaerida, Acanthometrida, Polycys- 

 tina, Collozoa, and Vesiculata. 



"These beautiful symmetrical and complex forms cannot be 

 due to the action of natural selection ; and sexual selection can of 

 course take no part in forming such organisms as these. We 

 seem here to have forced upon our notice the action of a kind of 

 organic crystallization, the expression of some as yet unknown 

 law of animal organization, here acting untrammelled by adap- 

 tive modification, or by those needs which seem to be so readily 

 responded to by the wonderful plasticity of the animal world." 

 Mivart. 



Having a single central capsule ... MONOCYTTARIA (or MONOZOA). 

 Having several central capsules ... POLYCYTTARIA (or POLYZOA). 



Traquairia. 



