DIGESTION AND ENDODERM OF LIMNOCODIUM. 125 
open meshwork, large spaces occurring between neighbouring 
cells, the cells being connected by ridges, which traverse the 
spaces. The cells themselves appear to be naked, and their 
protoplasm is irregularly aggregated so as to form masses with 
pseudopodia-like processes, and also clothing the ridges connect- 
ing cell with cell. Spherical nuclei (a), with spherical nucleoli, 
are placed at intervals in the protoplasm, and have a uniform 
appearance and size, which is characteristic of the endodermal 
nuclei throughout the gastric and gastro-vascular area. They 
measure about ;,'>>th inch in diameter, whilst the spaces in the 
meshwork are onan average about z,',,th by >'scth of an inch 
in the smallest and largest diameter. In the neighbourhood of 
the nuclei are numerous dense-looking masses of an ill-defined 
shape, which give to the cell-substance a certain opacity (0). 
In fig. 2 there are also seen vacuole-like spaces or clearer 
portions of the cell-substance, containing very dark minute 
granules. 
In both figures there are seen embedded in the protoplasmic 
net-work green unicellular organisms. 
In fig. 1 a large Huglena-like form (7) is embedded in a 
plasmodium formed by the confluence of cell-substance from 
some four or five cells. In the upper part of the figure two 
Protococci are. seen embedded in pseudopodia-like processes of 
the cell network. ‘The one to the left (y) is in a state of dis- 
integration, that to the right (z) has not yet been altered 
appreciably. . 
In fig. 2 the letter 2 points to an ingested organism, which has 
been almost entirely broken up and its colouring matter lost ; 
y warks a Protococcus reduced to the condition of a few 
coloured granules, whilst z is placed near a recently ingested 
Protococcus. 
I did not observe the movement of the pseudopodia-like 
lobes of this protoplasmic network during life, nor the actual 
process of the entry of a solid food particle into its substance. 
I may mention in this connection that the proximal region of 
the stomach in many specimens of Limnocodium was infested by 
a remarkable little free smimming, yet tubicolous Rotifer, which 
carried its tube about with it as it swam. 
This parasite appeared to escape altogether the embraces of the 
amceboid endoderm cells, as well as to be unaffected by the 
digestive secretions, if any such were present. 
STRUCTURE OF THE Gastric ENDODERM OF VARIOUS REGIONS, 
AS SEEN ON TREATMENT WITH REAGENTS. 
The true structure of the endoderm of the gastric tube becomes 
evident when specimens which have been treated with osmic 
