CLASSES OF PROTOZOA I3I 



of scattered granules (chromidia), and (2) the Mycetozoa, organisms 

 with somewhat complex fructifications, often classed as plants allied 

 to Fungi. As examples of the Proteomyxa, we have the interesting 

 Protomyxa in four phases : (a) encysted and breaking up into spores, 

 which (6) are briefly flagellate, (c) sink into amoeboid forms, and {d) 

 flow together into a composite " Plasmodium " ; Vampyrella, parasitic 

 on fresh -water Algae ; and many others. 



The Mycetozoa are well illustrated by Fuligo or yEtkalium septicum, 

 " flowers of tan," found in summer as a large plasmodium on the bark 

 of the tan-yard. The coated spores are formed in little capsules which 

 rise from the surface of the plasmodium. The spores may be first 

 flagellate, then amoeboid, or amoeboid from the first ; the characteristic 

 Plasmodium is formed by the fusion of the amoebae. 



B. Predominantly amoeboid Protozoa. — Rhizopoda. — The 

 simplest Rhizopods generally resemble Amoeba, and are ranked in the 

 class (3) Lobosa. They may reproduce simply by division, as does 

 Amceba itself, or mav liberate several buds at once (Arcella), or form 



Fig. 59. — Diagram of Protomyxa aurantiaca. — After Haeckel. 



I. Encysted ; 2. Dividing into spores ; 3. Escape of spores, at first 

 flagellate, then amoeboid ; 4. Plasmodium, formed from fusion of 

 small amoebae. 



spores which conjugate {Pelomyxa). Various forms, siich as Arcella, 

 are furnished with a shell. 



(4) The I.abyrinthulidea are represented by forms like Labyrinthula 

 on Algae, and Chlamydomyxa on bog-moss, which consist of a mass of 

 protoplasm spread out into a network, and of numerous spindle-shaped 

 units, which travel continually up and down the threads of the living 

 net. 



As (5) Heliozoa are classified the sun-animalcules [Actinosphcsrium, 

 Actinophrys sol), and others, in which there are stiff processes radiating 

 from a spherical body. Reproduction may be by division or by spore 

 formation ; skeletal structures may be represented by spicules. 



The (6) Foraminifera or Reticularia include an interesting series 

 of shelled forms in which the peripheral protoplasm forms branching 

 interlacing threads. A few simple forms occur in fresh water ; the great 

 majority occur on the floor of the sea at varying depths ; some 

 families are abundantly represented on the surface. The shell is 

 usually calcareous, more rarely arenaceous or chitinous. There is 

 sometimes dimorphism. Multiplication occurs by fission, or by the 

 formation of swarm-spores (amoeboid or flagellate). Foraminifera are 

 common as fossils from Silurian rocks onwards, and at the present day 

 are very important in the formation of calcareous ooze ; in this respect 

 Globigerina, with a chambered shell, is especially important. Species 



