68 BRITISH FRESHWATER RHIZOPODA. 
Dactylospherium vitrewm Herrwie & Lesser in Arch. f. 
mikr, Anat. X (1874), Suppl. p. 54, t. ii, £ La (non 13) ; 
ALLMAN in Journ. Linn. Soc., Zool. XII (1877), p. 266, 
f.1; Arcuer in Q. J. Micr. Sci. XVII, n.s. (1877), p. 344, 
t. xxi, f. 17; Parona in Boll. Scient. IT, an. 6 (1884), 
p- 56; Biocumann Mikr. Thierw. Sisswass. (1886), p. 11, 
t.1, f. 10, and ed. 2 (1895), p. 14, t.1,£.7; G.S. Waser in 
Journ. Linn. Soc., Zool. XXVIII (1901), p. 310. 
Dactylospheria polypodia Btrscuit in Bronn’s Thier- 
Reichs, I, 1 (1880), t. i, f. 11. 
Dactylospherium polypodiwm Lanessan Traité Zool., Prot. 
(1882), p. 48, f. 35. 
Dactylosphera polypodia Ray Lanxzster in Encycl. Brit. 
ed. 9, XIX (1885), p. 842, f. iv, 1-8; Loner in Atti Soc. 
Ligust. (1894), p. 16; Detace & Hérovarp Zool. coner. I 
(1896), p. 99, £. 107. 
Ameba vitrea Penarp Faune Rhiz. Léman (1902), p. 84, ff. 
According to the description given by Hertwig and 
Lesser this species has a spherical or sub-spherical 
body, from which radiate blunt or conical pseudopodia, 
in length usually about half the diameter of the body, 
and, like the border, consisting of a “ perfectly homo- 
geneous, quite clear, glassy-looking plasma.” Immersed 
in the protoplasm are a great number of greenish, 
strongly-refractive granules, varying in size. Two 
forms of the organism are described, one being green, 
the other a bright clear yellow. The coloured elements 
are crowded, filling the body-mass all but the narrow 
hyaline border, and preventing any view of the 
nucleus. In most, if not all, of the examples of the 
green form met with by Hertwig and Lesser, the entire 
superficies, including the pseudopodia, was covered by 
“peculiar protoplasmic hair-like prolongations, in 
which, however, no movement was perceptible.” 
Amongst other points of distinction Hertwig and Lesser 
say that the green examples lay motionless and at rest, 
appearing as more or less regular balls, and only these, 
with them numerous pro jected pseudopodia, showed a 
slow forward or backward movement. With the 
yellow-coloured individuals the case was different. 
These not only moved with comparative rapidity, aided 
