. Fresh-water biology. Freshwater biology. AMOEBOID PROTOZOA (SARCODINA) 219 KEY TO NORTH AMERICAN FRESH-WATER SARCODINA 1 (161) 2 (144) Pseudopodia without axial filaments. Class Rhizopoda Pseudopodia lobose, sometimes pointed but never anastomosing. Subclass Amoebea . 3 (21) Without shells Order Gymnamoebida . 4 4 One family recognized. Characteristics of the order. Family Amoebidae . 5 5 (6) Body and pseudopodia bristling with minute spicules. Dinamoeba Leidy. Representative species. . Dinamoeba mirabilis Leidy 1874. Very changeable in shape with many tapering pseudo- podia. Papillae-iike p
. Fresh-water biology. Freshwater biology. AMOEBOID PROTOZOA (SARCODINA) 219 KEY TO NORTH AMERICAN FRESH-WATER SARCODINA 1 (161) 2 (144) Pseudopodia without axial filaments. Class Rhizopoda Pseudopodia lobose, sometimes pointed but never anastomosing. Subclass Amoebea . 3 (21) Without shells Order Gymnamoebida . 4 4 One family recognized. Characteristics of the order. Family Amoebidae . 5 5 (6) Body and pseudopodia bristling with minute spicules. Dinamoeba Leidy. Representative species. . Dinamoeba mirabilis Leidy 1874. Very changeable in shape with many tapering pseudo- podia. Papillae-iike projections often appearing at the pos- terior extremity. Entire body sometimes surrounded by a jelly-lilse envelop. A contractile vacuole and two nuclei present. Habitat standing water. Size may reach 200 /*, including pseudopodia. Dinamoeba mirabilis. X lOo. (After Leidy.). Fig. 274 6 (s) Body smooth, without spicules. . 7 (8) Body usually enclosing symbiotic bacteria. Representative species. Large size. Nuclei many. Pelomyxa Greeff. Pelomyxa palustris Greeff 1870. 8(7) 9(10) 10(9) II 12 (14) (13) A very large form moving slowly by broad extensions of the ectoplasm. Endoplasm enclosing sand, brilliant corpuscles and bacteria; with numerous vacuoles in the ecto- plasm. Nuclei may number looo or more. Habitat ooze of ponds and sphagnous swamps. Maximum length 2000 m. P. carolinensis Wilson, described in American Naturalist, Vol. 34, p. 535, is apparently without symbiotic bacteria. Fig. 275. Pelomyxa palustris. X 25. (After Penard.) Body not enclosing symbiotic bacteria. .... 9 Ectoplasmic membranes produced between the pseudopodia. Hyalodiscus Hertwig and Lesser. Representative species. Hyalodiscus rubicundus H. and L. 1874. Body discoidal, moving by extending thin sheets of ecto- plasm which are penetrated by ray-like pseudopodia. En- doplasm reddish-yellow in color enclosing numerous vacuoles and one or more nuclei. Habitat ooze of ponds, not common. Size 40 to 60 /I. Fig. 27
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Keywords: ., bookcentury1900, bookdecade1910, booksubjectfreshwa, bookyear1918
