130 



THE AMOEBAE 



Their skeletons form our chalk, and they 

 and the Radiolaria are of great geological 

 interest. They are used, too, as indica- 

 tors in oil well drilling. More species of 

 Foraminifera have probably been named 

 than of all the other protozoa put together; 

 493 new species and 53 new genera of 

 Foraminifera were listed in the Zoological 

 Record for 1956, and of these, 470 species 

 and 48 genera were fossil. In contrast, 57 

 new species and 4 new genera of parasitic 

 protozoa were listed. And this was not an 

 exceptional year. 



ORDER AMOEBORIDA 



Members of this order have lobopodia 

 and are naked, without a test. All of the 

 parasitic and all but one of the coprophilic 

 Sarcodasida are found in this order. 



FAMILY NAEGLERIIDAE 



This family is transitional between 

 the Mastigasida and the Sarcodasida. 

 Both amoeboid and flagellate stages occur 

 in its life cycle. 



ORDER TESTACEORIDA 



Members of this order have a single- 

 chambered shell or test. 



FAMILY ARCELLIDAE 



The test is simple and membranous, 

 without foreign bodies, platelets or scales. 

 The pseudopods are filose or simply 

 branched and do not anastomose. There 

 are many genera and species of free-living 

 protozoa in this family. They are found 

 commonly in fresh water, swamps, etc. 

 One species is coprophilic. 



Genus CHLAMYDOPHRYS 

 Cienkowski, 1876 



The test is rigid and circular in cross 

 section. The nucleus is vesicular, with a 

 prominent endosome. The cytoplasm is 

 differentiated into distinct zones, and re- 

 fractile waste granules are present in it. 

 The pseudopods are branching. 



Chlamydophrys slercorea Cienkowski, 

 1876 has an oval, white porcelaneous, thin, 

 smooth shell open at the pointed end. It 

 measures about 20 by 14 /i. The pseudo- 

 pods are filose. Somewhat smaller naked 

 amoebae may also be seen. The cysts are 

 uninucleate, 12 to l'b\i in diameter, with 

 thick, irregular, brownish walls. Multi- 

 plication is by budding. C. slercorea is 

 coprophilic and may also be found in fresh 

 water. 



Genus NAEGLERIA Alexeieff, 

 1912 emend. Calkins, 1913 



The flagellate stage has 2 flagella. 

 The amoeboid stage has lobopodia and re- 

 sembles Vahlkanipfia. The nucleus is 

 vesicular, with a large endosome. The 

 contractile vacuole is conspicuous. The 

 cysts are uninucleate. Naegleria lives on 

 bacteria and is free-living in stagnant 

 water or coprophilic. 



Naegleria gruberi (Schardinger) (syn. , 

 Dimasligamoeba gruberi) is found in stag- 

 nant water and is also coprophilic. The 

 active amoebae are 10 to 36 by 8 to 18 p. 

 and have a single vesicular nucleus 3 to 

 4fj, in diameter. The nucleus has a cen- 

 tral endosome and sparse granules of 

 peripheral chromatin. The flagellate stage 

 is 18 by 9 (i, ovoid, and has 2 equal anter- 

 ior flagella. It can be produced from the 

 amoeboid stage by flooding the culture with 

 distilled water and exposing it to air. The 

 cysts are spherical, 8 to 12 /i in diameter, 

 translucent, with a single nucleus and sev- 

 eral large spherical chromatoid bodies 

 when first formed. The cyst wall is double, 

 and the outer wall is perforated by 3 to 8 

 pores. 



Genus TRIMASTIGAMOEBA 

 Whitmore, 1911 



The nucleus is vesicular, with a large 

 endosome. The flagellate stage has 3 fla- 

 gella (4 according to Bovee, 1959) and the 



