430 ZOOLOGY. 



Order 1, Lobosa. Ehizopoda with blunt pseudopodia 

 which do not anastomose to form networks. Amoeba is an 

 example of the Lobosa. Some of the species, e.g. Difflugia 

 and Arcella, possess a chitinous cuticle or shell enclosing 

 the greater part of the body but leaving one part uncovered, 

 from which pseudopodia are protruded. 



Order 2, Foraminifera. Pseudopodia fine, branched, and 

 anastomosing ; body contained in a shell which may be chiti- 

 nous, calcareous, or arenaceous ; shell usually compound, con- 

 sisting of chambers successively formed and communicating 

 by a terminal aperture to each chamber or by numerous 

 perforations. In the life-history there is an alternation of 

 generations, one form with large initial chamber and a single 

 large nucleus gives rise after division of the nucleus to a large 

 number of minute biflagellate zoospores which conjugate 

 in pairs, and each zygote thus formed becomes a micro - 

 spheric form, that is a form with a small initial chamber, 

 which by simple division without conjugation gives rise again 

 to the megalo spheric form with large initial chamber. 



Order 3, Eadiolaria. Pseudopodia long and delicate, 

 either free or anastomosing ; imbedded in the protoplasm 

 is a " central capsule " of chitin, within which is a large 

 and complex nucleus, or sometimes several nuclei. Skele- 

 ton in many forms siliceous, either of separate spicules, or 

 of a firm connected framework, of spherical, stellate, or 

 discoid shape, frequently produced in radiating spines : in 

 one division the skeleton consists of the chitinous substance 

 acanthin : in some cases no skeleton is present. Usually 

 symbiotic unicellular organisms containing chloroplasts of 

 yellow colour are found living in the protoplasm of the 

 Kadiolaria; they are usually regarded as Algae, but by 

 some authorities as Flagellate Protozoa. Keproduction by 

 simple fission, which in some cases leads to the formation 

 of compound or colonial organisms, or by the formation of 

 flagellate zoospores ; no conjugation has been observed. 



CLASS : SPOROZOA. 



Protozoa which are all parasitic, destitute of organs of 

 locomotion in their principal stages, without contractile 

 vacuole, enclosed by a distinct cuticle, absorbing food only 



