THE ANIMAL KINGDOM 375 



Order 4. Foraminifera. Body enclosed in a single or many- 

 chambered shell of siliceous or calcareous material, through 

 the numerous pores of which delicate pseudopodia extend. 



Example: Globigerina bulloides, a marine form, both pelagic 

 and bathybic down to depths of 18,000 ft. Chalk beds are 

 composed largely of the discarded shells of this species. 



Order 5. Mycetozoa. Large amoeboid forms, multinucleated, 

 with numerous contractile vacuoles and often colored red, 

 orange, yellow, or green. Reproduce by spores and regarded 

 as border-line forms between animals and plants. 



Example: Mucilago spongiosa and other slime molds, found 

 on decaying wood. Some colonies may be several inches in 

 diameter. 



SUBCLASS 2. ACTINOPODA. Floating forms with radi- 

 ating UNBRANCHED PSEUDOPODIA. 



Order 1. Heliozoa. A spherical body with fine raylike pseudo- 

 podia and often a siliceous skeleton. Cytoplasm is divided 

 into an outer cortex and an inner medulla, the latter containing 

 one or more nuclei. Mostly fresh-water forms. 



Example: Actinospherimn eichhomi, common in fresh water 

 (Fig. 209, C). 



Order 2. Radiolaria. Marine forms, usually with a siliceous 

 skeleton. The spherical body is divided by a perforated 

 chitinous central capsule into an extracapsular cortex and an 

 intra capsular medulla containing one or more nuclei. 

 Example: Acanthometra elastica (Fig. 209, D). 



CLASS III. SPOROZOA. Endoparasites in the cells and 

 tissues of many animals. No vacuoles. Body is covered by a 

 thick pellicle through which food is absorbed. Reproduction 

 by spores. 



SUBCLASS 1. TELOSPORIDIA. Intracellular parasites 

 whose life history terminates in spores. 



Order 1. Gregarinina. Intestinal parasites of arthropods and 

 annelids. 



Example : Gregarina blattarum, found in the digestive tract of 

 roaches. The body of the gregarine {trophozoite stage) is 

 divided by a transverse partition into an anterior protomerite 

 and a posterior nucleated deutomerite (Fig. 210). The epimer- 

 ite is an additional segment in front of the protomerite which 

 is well defined during only a part of the life cycle. In repro- 



