266 E. RAY LANKESTER, ON THE 
vessels and septal muscles, considerably enlarged. The 
most anterior pair, which exists in the twelfth ring, are 
somewhat round and full, pale in colour, and with an im- 
mensely vascular surface, the vessels running parallel to 
one another, and frequently so numerous as to give the 
organs a bright-red colour. They are firmly attached to the 
walls of the cesophagus, but do not appear to have any com- 
munication with its interior. When opened they are found 
to contain either a single hard crystalline mass or numerous 
smaller bodies of a similar appearance, when placed under 
the microscope, to that drawn in fig. 10. The wall of the 
pate of pouches is thin, and the presence of the hard bodies 
heueath can be detected by simply pressing the glands. 
When a porticn of the crystalline substance is treated with 
nectic acid, it dissolves with great effervescence. It is there- 
fore probable that the substance is carbonate of lime. 
These glands do not always contain crystalline bodies, and 
occasionally a worm is found in which all three pairs of 
esophageal appendages have lost their vascularity and size. 
I am not able to give any clue as to the function of this first 
pair of glands; it may be connected with the formation of 
the egg-capsule, which is said to contain carbonate of lime; 
on the other hand, it may be a provision for disposing of any 
superabundance of mineral matter in the blood. I have 
frequently found the crystalline bodies passed into the 
cesophagus and lodged in the capacious crop. The second 
and third pairs of cesophageal glands are situated in the 
thirteenth ring, and have a form and appearance differing 
from the first. They are a little smaller, and their walls are 
much thicker, but no less vascular, than the first pair. They 
contain a milky fluid, which, when examined with the micro- 
scope, is found to consist of very minute granules, somewhat 
similar to those of the hepatic membrane of the intestine. 
A very thin section, made vertically through one of these 
glands, shows the structure drawn in fig. 2, an inner epithelial 
coat, a vascular region in which the blood-vessels are arranged 
in loops as seen in the figure, and an outer more delicate 
membrane, forming the sheath of the organ on which the 
externally visible vessels extend; these, as in the anterior 
pair of glands, are very numerous, and run parallel to one 
another. 
The arrangement of the vessels interiorly in loops is very 
remarkable, and may be easily observed when the vessels are 
naturally injected. All three pairs of glands present this 
structure. The use of the milky secretion contained in the 
second and third pairs may be in the process of digestion ; 
