130 BRITISH FRESHWATER RHIZOPODA. 
ns. (1877), p. 107, t. viii, ff. 1-3; Buck in Zeits. f. wiss. 
Zool. XXX (1878), pp. 5,12; Maaar in Atti Soc. Ital. 
XXI (1878), pp. 314, 319, and in Boll. Scient. I, an. 2 
(1880), p. 35; Birscutr in Bronn’s Thier-Reichs, I, 1 
(1880), t. ii, £.8; Lanessan Traité Zool., Prot. (1882), p. 51, 
f. 39; Parona in Boll. Scient. I, an. 4 (1882), pp. 52, 56; 
Brocumann Mikr. Thierw. Siisswass. (1886), p. 12, t. 1, 
f. 15, and ed. 2 (1895), p. 15, t. i, f. 11; Carrawzo in Boll. 
Scient. IIT, an. 10 (1888), p. 91; Saccur in Boll. Scient. 
III, an. 10 (1888), p. 44; Loner in Atti Soc. Ligust. V 
(1894), p. 17; Detace & Hérovarp Zool. concr. I (1896), 
f. 122; Catxins Prot. (1901), f.13c; Prwarp in Rey. 
Suisse Zool. IX (1901), p. 238, and Faune Rhiz. Léman 
(1902), p. 180, ff., and p. 666; CasH in Journ. Linn. 
Soc., Zool. XXTX (1904), p. 218. 
Amphizonella flava Greurr in Arch. f. mikr. Anat. IT (1866), 
p. 329, t. xviii, f. 19; Creventt and Macer in Rend. R. 
Ist. Lomb. (2) III, p. 369; Tripp in Proc. Bristol Nat. 
Soc. n.s. IV (1870), p. 19; Macar in Atti. Soc. Ital. XXI 
(1878), p. 314. 
Test discoid, generally circular, concave, in the 
young state hyaline and flexible, becoming rigid and 
brown with age; sometimes, in the latter condition, 
punctated on the convex surface, or, according to 
Archer, presenting an appearance of faceting or 
shagreening, “due to little rounded, closely-posted, 
scattered scrobiculi.” The flexibility of the test, when 
young, is shown by its assuming a variety of forms, 
being at one moment discoid, at another folded in upon 
itself, wholly or partially, or rolled together scroll-lke. 
A short finger-like pseudopod is sometimes protruded 
from between the folds. Nucleus central; contractile 
vesicles several, peripheral. 
Dimensions : Diameter of test 40-45 p. 
Amongst submerged vegetation (e.g. Hypnum 
fluitans) in ponds, and amongst Sphagnum. In 
Cheshire ponds abundant, chiefly in the spring months, 
associated with Microgromia socialis. 
The variations of figure of the test of Psendochlumys, 
when young, correspond with the activities of the 
animal. There is a close attachment of the plasma- 
