THE SARCODINA 



219 



small amoeboid form which, like Pseudospora, preys upon algae 

 (Fig. 86), devouring the contents of the cell, and multiplying in the 

 free state by binary fission. It also encysts and breaks up within 

 the cyst by multiple fission to form a number of amcebulae, which 

 creep out and grow up into the adult form. 



A large number of other genera are referred to the Reticulosa, 

 for the most part so little investigated as regards their develop- 

 ment and life-history that it is impossible to deal with them com- 

 prehensively in a brief space. For an account of them see Delage 

 and Herouard (6, p. 66), Hickson (248), and Rhumbler (288). 



2. Lobosa. This suborder comprises a great number of organisms, 

 which it is convenient to subdivide into (a) Nuda (Gymnamoebae), 



'-. * 



\\ . -4>t''ii^v >: >' 



^^ffm^.^ 



FIG. 86. Vampyrella lateritia: various forms. A, Fgee Heliozoon-iike phase; 

 B, creeping amoeboid phase ; C, amoeboid form attached to a <?ow/erw-fila- 

 ment ; D, a similar form ; it has broken the algal filament at a joint, and has 

 emptied one cell of its contents. A and B after Hoogenraad ; G and D after 

 Cash and Hopkinson. 



with no shell ; and (b) Testacea (Thecamoebae, Thalamophora), with 

 a shell or house. 



General Characters. Familiar examples of the Lobosa Nuda are 

 furnished by the species of the genus Amoeba and allied forms. A 

 very large number of free-living amoebae have been described and 

 named, but it is very doubtful how far they are true species ; some 

 of them, with pronounced and constant characteristics, such as 

 Amoeba proteus (Fig. 2) and A. verrucosa (Fig. 23), are probably 

 ' good ' species ; others, such as A. Umax and A. radiosa, are 

 probably forms that may occur as phases in the development of 

 other species of amoebae or of other organisms, such as Mycetozoa. 



