Digestive Processes in Arachnids. By II. M. Bernard. 431 
from the other diverticula. As far as my own researches with the 
Chernetidae, Scorpionidae, Araneidae, and Galeodidae extend, none of 
the diverticula of the alimentary canal are specialized into glands ; 
they are all simple digesting diverticula.* 
The cells lining the alimentary diverticula of Euscorpio differ 
from those of the Chernetidae in being somewhat more specialized. 
They are smaller, and each contains one enormous food-vacuole. 
Between the food- vacuole and the lumen of the gut, there is a thick 
layer of staining protoplasm (fig. 3). These cells are sometimes found 
long and narrow, the food-vacuoles bulging out the individual cells 
in such a way that in section there is a confused mass of cells out of 
which it is difficult to make any order. In other places the digesting 
cells are short and square, and appear to have plenty of room 
(fig. 3). 
Within the food- vacuoles, the typical food-globules are found in 
all stages of disintegration, ending as in the Chernetidae in the 
same minute crystal-like bodies which, however, tend rather to be 
long and rod-shaped than rhomboidal. These are excreted, passing 
lengthwise through the thick cushion of protoplasm at the distal 
boundary of the cell. Cases can be found in which the cushion 
has “ crystal ” bodies standing out all over it like the bristles of a 
hedgehog. This fact led me to see if I could find any case of the 
discharge of these faecal bodies by the bursting of the vacuoles. I 
am inclined to think that this does not take place. The “ crystal ” 
bodies in Amoebae pass directly through the ectosarc, round the outer 
edge of which they are often found adhering in considerable numbers, 
and further in the Chernetidae they must pass out directly through 
the protoplasm of the digestive cells. 
As in the Chernetidae, these faecal crystals in Scorpio are the 
chief constituent of the contents of the hind-gut, which, owing to its 
length, has no need of a stercoral pocket. 
At the anterior end of the hind-gut, however, one is aware of the 
presence of large clear bodies mingled with the faeces which give the 
latter, when viewed by transmitted light, a mottled appearance. On 
close examination, these are found to be cells, which, owing to the 
crowding of the digestive cells when their vacuoles are full, had broken 
away and travelled down the gut. Such detached cells are found in 
enormous numbers, generally in groups (fig. 4), in all the wider 
lumina of the alimentary diverticula, and many of them at least, 
if not all of them, ultimately arrive with the faeces in the hind-gut. 
During this passage, the gradual digestion of the contents of their 
vacuoles goes on, and the excretion of the crystalline remains can 
be seen to take place as in the stationary cells (fig. 4). But what 
* As such digesting diverticula would naturally give all the reactions of the 
different secretions necessary to the digestive process, the attempt to show that these 
diverticula are pancreatic glands by means of chemical reagents cannot be couclusive. 
Cf. Griffith aud Johnstone, Proc. Roy. Soc. Edinburgh, xv. 
