536 
CLIFFORD DOBELL. 
racan heliozoon of very small size (10 /u to 22 /u in diameter) ; 
spherical, with numerous very fine radiate pseudopodia (axo- 
podia) with streaming granules and with axes rooted in a 
centrally placed centroplast ; no stalk, no contractile vacuole, 
no gelatinous investment, no spicular skeleton, no sharply- 
differentiated ectoplasm and endoplasm. Nucleus single, 
large, excentric ; vesicular, with large central karyosome. 
Reproduction by equal binary fission, in which nucleus divides 
by mitosis, the centroplast playing the part of a centro- 
sorne. Free-floating or creeping; solitary; marine. Food 
chiefly vegetable matter (in cultures, swarm-spores of green 
algae). 
References. 
Brauer, A. (1894).—' " Ueber die Encystirung von Actinosphserium 
eichhorni Ehrbg.,” ‘ Zeitschr. wiss. Zool.,’ vol. lviii, p. 189. 
Biitschli, O. (1892). — “Ueber die sogenannten Centralkorper der Zelle 
und ihre Bedeutung,” ‘Yerhandl. naturhist.-med. Yer. Heidel- 
berg,’ vol. iv (n.f.), p. 535. 
Dobell, C. (1908). — “The Structure and Life-history of C opr onion as 
subtilis, n. g., n. sp.,” ‘Quart. Journ. Micr. Sci.,’ vol. 52, p. 75. 
(1909). — “Researches on the Intestinal Protozoa of Frogs and 
Toads,” ibid., vol. 53, p. 201. 
(1911). — “The Principles of Protistology,” ‘Arch. f. Protis- 
tenk., vol. xxiii, p. 269. 
(1914). — “ Cytological Studies on Three Species of Amoeba,” 
ibid., vol. xxxiv, p. 139. 
Grenadier, H. (1869). — “ Bemerkungen fiber Acanthocystis viridis, 
Ehrbg. sp.,” ‘ Zeitschr. wiss. Zool./ vol. xix, p. 289. 
Heider, K. (1894). — Demonstration of Sections of Raphidiophry s, 
‘Yerhandl. deutsch. Zool. Ges.,’ vol. iv, p. 94. 
Hertwig, R. (1877). — “ Studien fiber Rhizopoden,” ‘ Jena. Zeitschr., 
vol. xi, p. 324. 
(1898). — “Ueber Kerntlieilung, Riclitungskorperbildung und 
Befruclitung von Actinosphserium eichhorni,” ‘Abh. bayr. 
Akad. Wiss.,’ vol. xix. 
Jameson, A. P. (1914). — “A New Phytoflagellate (Parapolytoma 
satura, n, g., n. sp.) and Its Method of Nuclear Division,” 
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