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Transactions of the Society. 
food-spherules are to be met with in the lumen of the tube. Any of 
these which fail to find their way back again into the digesting cells 
would be carried on into the hind-gut and so into the stercoral 
pocket. Comparatively few, however, so escape, as some selective 
process evidently goes on at the aperture of the hind-gut, otherwise 
it would be impossible to account for the separation of the faecal 
“ crystals ” from the coagulum. The epithelium of the hind-gut 
apparently has no power of dissolving down the food-globules into 
assimilable fluids. 
Before escaping into the blood, the assimilable fluids resulting 
from the dissolution of the food-globules have to pass through a layer 
of cells which clothes the whole alimentary canal externally. These 
cells seem to be characteristic of the Arachnids, but are differently 
developed in different genera. Bertkau has called them the “fat- 
body ” cells, and suggests that the functions of this “ fat-body ” are 
probably supplementary to those of the alimentary canal. My own 
observations tend fully to confirm this latter proposition, viz. that 
these mesodermal cells, clothing the alimentary canal externally, 
play a definite, and in some cases a very important role in alimen- 
tation. But I prefer to use the more indefinite description of these 
cells as the peritoneal covering of the alimentary canal. 
In the Ohernetidae, these peritoneal cells are often so vacuolated 
as almost to appear like a layer of connective tissue with large nuclei 
suspended on the threads (fig. 1). As far as one can judge by 
appearances alone, one would say that this is in order to allow the 
nourishing fluids to flow freely through the wall of the alimentary 
canal into the blood. 
In one specimen examined, the animal was infected with bacteria, 
and it is perhaps significant of the nourishing character of the fluids 
contained in or passing through these peritoneal cells that the great 
round nests of bacteria show a decided tendency to form within these 
cells. 
To sum up, then, we find that the juices sucked in are turned by 
the digesting cells of the Ohernetidae into homogeneous globules, in- 
distinguishable from the so-called fat-globules of Amoebae ; that these 
are slowly dissolved, leaving small crystalline bodies also indis- 
tinguishable from the so-called crystals of Amoebae; that these 
bodies are excreted and eventually found as the chief constituent of 
the faeces in the stercoral pocket. 
ScORPIONIDiE. 
The usual claim that Scorpio has salivary glands is incorrect. 
The whole of the internal space of the cephalothorax in these animals 
is so compressed longitudinally that the single pair of cephalothoracic 
diverticula comes so far forward that it has been mistaken for a 
salivary gland, whereas serial sections show that it does not differ 
