340 MR. G. 8S. WEST ON SOME BRITISH 
position to the chlorophyll-bodies of R. viridis. The chlorophyll- 
bodies which I observed (zoochlorellids?) were numerous, but 
confined towards the periphery of the body. I think that the 
Welsh examples are best described as forms of R. pallida, Schulze, 
containing chlorophyll-bodies. 
Gen. AcantHocystTIs, Carter. 
66. ACANTHOCYSTIS CHmHTOPHORA, Leidy, Freshw. Rhiz. N. 
Amer. 1879, p. 264, t. xlii. ff. 1-6.—Trichoda chetophora, 
Schrank, 1803. Actinophrys viridis, Lhrenb. 1833 ; Infus. 1838, 
p- 304, t. xxxi. f. vii. Acanthocystis turfacea, Carter, in Ann. 
Mag. Nat. Hist. 1864, xiii. p. 36, t. ii. f. 25; Hertwig & Lesser, 
in Archiv fiir mikr. Anat. 1874, x. Suppl. p. 204. A. viridis, 
Greeff, in Archiv fiir mikr. Anat. 1869, v. p. 481, t. xxvi. 
ff. 8-17. A. pallida, Greeff; 1. c. p. 489, t. xxvii. f. 19. 
A somewhat uncommon species, of which the two most in- 
teresting forms observed were the following :— | 
From Terrington, N. Yorkshire. A colourless form, with the 
smaller spines rather more numerous than the larger ones. 
Diameter of body 74 4; length of large spines 40-44 py; length 
of small spines 16-19 yp. 
From Barnes Common, Surrey. A specimen containing 
numerous oval chlorophyll-bodies and with the outer proto- 
plasmic envelope of a brown colour. Only the delicate spines 
were observed and these were much longer than usual. Diameter 
of body 67-76 y«; length of spines 38-54 p. 
67. ACANTHOCYSTIS PALUDOSA, sp.n. (Pl. 30. figs. 32, 33.) 
Body spherical, consisting of finely granular protoplasm, often 
colourless, but sometimes bright green from the presence of 
numerous chlorophy!l corpuscles of variable size. Nucleus central 
or subcentral, rarely visible inthe living animal. Outer surface of 
the body firm, sometimes of a pale yellow colour, beset with very 
numerous short siliceous spines. Spines delicate, simple, irre- 
gularly radiating, and with pin-head-like bases. Pseudopedia 
comparatively scanty, long and extremely delicate, beset along 
their length with numerous fine granules. 
Diameter of body without spines 43-49 » ; length of spines 
53-8 p. 
In ponds and ditches, Sheep’s Green and Wicken Fen, 
Cambridgeshire. Near Shelf and near Ilkley, W. Yorkshire. 
This animal is undoubtedly the same species as the 
