INFUSORIA. rJl 



a latticed shell. The extra-capsular cells [yellow bodies] are wanting. Acantlio- 

 inetra pellucida Joh. Mull. 



II. Polycyttaria. Radiolaria which form colonies with several central capsules- 

 Amongst the Sphaerozoa a skeleton is wanting or consists of single pieces not 

 joined together. Collozoum inerme E. Haeck. Splicer ozoum punctatum Joh. 

 Mull. In Collosplusra the skeleton consists of simple latticed spheres, each of 

 which encloses a central capsule, Collosplicera Huxley i Joh. Mull. 



\ 



FIG. 132 Eucyrtidium cranoides (after E. Haeckel). 



CLASS II. INFUSORIA.* 



Protozoa with a definite form and provided with an external 

 membrane, bearing either flag ella or cilia. Mouth and anus usually, 

 contractile vacuole and one or more nuclei always present. 



Infusoria were discovered towards the end of the 17th century 



* Ehrenberg, " Die Infusionsthierchen als vollkommene Organismen," 183S. 

 Balbiani, "Etudes sur la Reproduction des Protozoaires," Journ. de la Phys., 

 Tom. III. Balbiini, "Recherches sur les phenomenes sexuels des Infusoires," 



