76 BRITISH FRESHWATER RHIZOPODA. 
including desmids and other alge, and sometimes also 
rotifers and entomostraca. 
Such a mass of foreign matter renders a study of 
the physiological structure of this organism difficult in 
adult individuals; but in younger examples, sometimes 
though rarely met with, the body-substance being 
transparent, the “shining bodies,” of rounded or oval 
figure, can readily be seen, imbedded in the hyaline 
and homogeneous protoplasm, besides numerous vesi- 
cular spaces, lying, as described by Greeff, in the 
richly-granular intervening substance, the whole not 
unlike Actinophrys Hichhornvi, but not so regular or 
compact. The vesicles vary in size, and their place 
in the protoplasmic substance is subject to constant 
change, such change being governed by the move- 
ments of the organism. In addition to the elements 
described, there are always present, in this species, 
rod-like bacteria scattered through the protoplasm in 
great numbers. 
Greeff remarks that the body, in Pelomyxa palustris, 
consists of pure protoplasm, and is composed of two 
strata—an outer cortical one and an inner parenchyme. 
The former is hyaline and homogeneous; it is the 
chief seat of contractility, and hence in it the loco- 
motive power resides. The whole inner parenchyme 
is of thinner consistence and is but passively moved ; 
itis richly granular and filled with watery vacuoles, 
often so crowded that the substance appears reticu- 
lately interrupted. The two strata are not sharply 
marked off, but pass gradually into one another. In 
the so-composed body-mass there occur, then, three 
structures—(1) nuclei; (2) hyaline and homogeneous 
bodies of roundish, ovoid, or irregular figure, and glossy 
appearance (the glanzhsi “per; and (3) fine bacilliform 
bodies. These have for some time been regarded b 
most authors as symbiotic bacteria, and that this is 
their true nature has now been proved. 
P. palustris is multi-nucleated. The nuclei are 
small and obscure; irregularly distributed between 
