AMOEB1NA. 905 



Saville Kent, Manual of the Infusoria, i. p. 322-4; Allman, J. L. S. xiii. 1887, 

 P- 435- 



The Amoebina may be classified as follows : 



1. Nuda s. Gymnamoebae : devoid of a test; in some instances there is 

 a coagulated superficial pellicle, or a complete gelatinoid, chitinoid, or spinulose 

 coat; pseudopodia lobose, pointed, &c. 



Amoeba (with Lithamoeba, Ouramoeba, and Endamoeba] Deinamoeba s. 

 Chaetoproteus, covered by minute spicule-like processes; Hyalodiscus, no pseudo- 

 podia, but the disc flows onwards without change of shape ; Plakopus, with mem- 

 branous expansions united together, so as to include spaces, sometimes resembling 

 Hyalodiscus^ ; Dactylosphaerium with rounded body, digitiform pseudopodia, and 

 green or yellow bodies; ? Podostoma, resembles Dactylosphaerium, but has two 

 vibratile pseudopodia produced temporarily for the inception of food ; Pelomyxa 

 (=.Pelobius\ pseudopodia broad, and wave-like, non-contractile vacuoles, and 

 nuclei numerous, gorged more or less with mud, sand, food; Amphizonella, a 

 gelatinous envelope pierced by the digitiform pseudopodia, inert ; Zonomyxa, an 

 elastic chitinoid investment, pseudopodia more or less branched, minute violet 

 vacuoles, many slowly (?) contractile vacuoles and nuclei; Trichosphaerium (= 

 Patkymyxa\ a coat of vertical rods implanted in a membrane, with gaps for the 

 long cylindrical pseudopodia, multinucleate, marine. 



2. Testacea s. Lepamoebae : a test either chitinoid and then flexible or rigid, 

 in some incrusted with foreign bodies, or composed of chitinoid or siliceous plates 

 cemented together or borne by a chitinoid membrane. 



(i) With digitiform, sometimes slightly branched pseudopodia (=Arcellina, 

 Biitschli). 



Cochliopodium, a flexible cup-shaped chitinoid test, closely adherent to body ; 

 Arcella, a semi-globular, rigid, complex test (p. 898), dark-brown, with aperture 

 limited by a horizontal flange or rim, ? young forms Pyxidicula and Pseudochlamys; 

 Centropyxis (=Echinopyxis), test chitinoid, but aperture and fundus excentric in 

 opposite directions, smooth or spinose, dark-coloured; Hyalosphenia, test ovoid 

 or pyriform, compressed, chitinoid, structureless, colourless or yellowish ; Quadrula, 

 test pyriform, compressed, colourless, composed of squarish chitinoid (? siliceous) 

 plates in transverse rows ; Nebela, test pyriform, compressed, with or without 

 appendages, typically composed of a chitinoid membrane with large and small oval 

 or rod-like siliceous plates, sometimes intermixed; Heleopera, test ovoid, com- 

 pressed, chitinoid with a reticulation of dotted lines ; Difflugia, test of variable 

 shape, globular to elliptical, often provided with processes, commonly compressed, 

 aperture terminal or sub-terminal, composed of very various foreign bodies cemented 

 together, such as sand-grains, diatoms, frustules, or of a chitinoid membrane with 

 scattered foreign bodies, or oval and rod-like bodies (as in Nebela) \ Lecquereusia= 

 Difflugia spiralis, retort-shaped, with internal septum (p. 898) ; Petalopus, ? a test, 

 pseudopodia ending in plate-like expansions; Arcellina, test chitinoid, with a pro- 

 duced aperture and pores opening each on the summit of a tubercle, (?) globular, 

 ovate, as large as a hemp-seed, marine. 



1 Plakopus and Hyalodiscus are supposed by Leidy to be identical ; so too by Mereschkowski 

 (A. M. A. xvi. pp. 194-5). Zopf believes them to be the same as Klein's Vampyrdla pedata, a 

 Proteomyxan. 



