134 BRITISH FRESHWATER RHIZOPODA. 
Test chitinous, variable in size and contour; usually 
carrying from four to six well-developed, curved, 
and occasionally bifid spines; opaque or semi-trans- 
parent, with an irregularly margined orifice, and not 
infrequently covered wholly or partially with fine 
sandy particles, or diatom shells; the excentric 
mouth being always at the shallow extremity. Hndo- 
plasm and pseudopodia as in Difflugia; the latter 
sometimes knotted or branching. 
When encisted the protoplasm forms a spherical 
ball in the thicker part of the test; it is filled with 
granular matter and green or colourless globules. 
Dimensions variable: Diameter of test 110-150 pw; 
length of spines 20 or more. Diameter of mouth 
50-60 p. ' 
In ponds and ditches and amongst Sphagiwm and 
wet moss, associated with Difflugia, etc. ; frequent. 
The species may readily be distinguished from 
Difflugia constricta by its larger size and more ex- 
panded outline, as well as by the branching of the 
pseudopodia. It is usually most plentiful amongst wet 
Sphagnum in swampy ground. Examples occurring 
in such situations are, as a rule, free from extraneous 
matter, except diatom shells, of which in some cases 
they appear as if built up. Those without incrusta- 
tions have an irregular and delicate mesh-work on the 
chitinous surface and usually have the longest spines. 
Examples vary greatly in size. West (in ‘ Journ. 
Linn. Soc.,’ Zool., vol. xxviii) records individuals from 
Athry Lough, W. Ireland, measuring 450 «4 without 
the spines. The transparent chitinous test sometimes 
exhibits a cancellated or punctated surfacing. Some 
Terrington Carr examples were found by the same 
author to be of a pale yellow colour and minutely 
scrobiculate. The scrobiculations were irregularly 
disposed, being scattered more or less in groups, 
and between them were numerous much smaller 
punctulations. 
