58 BRITISH FRESHWATER RHIZOPODA. 
anteriorly, and the animal moves forward in an almost 
direct line, having a wide frontal margin of clear 
ectoplasin. The nucleus and contractile vesicle are in 
the posterior region, the latter usually in advance, 
and the endoplasm contains, besides food-particles, a 
variable number of minute crystalline bodies. 
Dimensions + Length 50-60; average breadth 
about 15 Me 
In ponds, etc., with Amaba guttula, and generally 
as plentiful. 
This species is more active than Ameba guttula. Its 
mode of progression approaches that of some forms of 
A. proteus and A. villosa, but it is more uniform, and 
Penard points out its peculiar habit of changing the 
direction of its march by a movement of the anterior 
portion of the body en inasse, to right or left, whilst 
the posterior remains stationary. This habit is cer- 
tainly rare amongst the Amebe. 
9, Ameba verrucosa Ehrenberg. 
(Plate V, figs. 1-3.) 
Ameha verrucosa WHrenperc Infus. (1838), p. 126. t. viii, 
f. xi; Prircuarp Hist. Infus. (1842), p. 166; new ed. 
(1852), p. 202; and ed. 4 (1861), p. 549; Prrry Kenntn. 
kleinst. Lebensf. (1852), p. 188; Scumarpa in Denkr. K. 
Akad. Wiss. Wien, VII (1854), 2, pp. 14, 25; Carrer in 
Ann. Nat. Hist. (2) XX (1857), pp. 37, 40, t. 1, ff. 12,18; 
Pick in Ver. Vereins Wien, VII (1857), p. 36; Carpenter 
Foram. (1862, Ray Soc.), pp. 36, 39, t. iv, £8; Rymzr 
Jonus Anim. Kingd. ed. 4 (1871), p. 20; Fromenrer 
Etudes Microz. (1874), p. 348, t. xxix, f. 7; Lemy in 
Proc. Acad. Nat. Sci. Phil. 1874, p. 167; op. eit. 1876, 
p. 198; op. cit. 1878, p. 158; and Freshw. Rhiz. N. 
Amer. (1879), p. 58, t. ii (excl. f. 37); Maaar in Rend. 
R. Ist. Lomb. (2) IX (1876), p. 441; Carraneo in Boll. 
Scient. I, an. 1 (1879), pp. 7, 27, 57; op. e’t. IL, an. 10 
(1888), p. 93; and in Atti Noc. Ital. XXII (1880), 
p. 254; Parona in Boll. Scient. I, an. 2 (1880), pp. 46, 
48, and an. 4 (1882), pp. 51, 56; Hirencock Synops. 
Freshw. Rhiz. (1881), p. 5; Vuspovsky Thier. Org, 
