66 
SUPPLEMENT 
At the end of this first part of the intestinal canal comes 
the oesophagus, which in the species where there is no buccal 
mass, is the direct continuation of the buccal cavity ; but 
which, in the others, takes its origin at its upper part, so that 
the plane of the latter is much lower. 
Accompanied in its traject by some salivary glands, often 
rather long, at least in the species where mastication takes 
place, or shorter in those in which this function does not 
exist, the oesophagus is more or less dilated, and constitutes 
the stomach. 
This part of the intestine is sometimes enlarged, solidified by 
muscular fibres pretty thick, and constituting a sort of gizzard, 
as may be seen in the lumbricus terrestris. But most fre- 
quently it is membranaceous, and is continued, through the 
whole thoracic portion of the trunk, undergoing some dilata- 
tions, more or less marked, or being provided with sorts of 
cceca opposite to each interval of the articulations. These 
dilatations are often determined, in a great measure, by the 
plenitude of the stomach, and then its parictes are very thin. 
In the contrary case, they have a very great thickness, as 
much in consequence of that of the muscular stratum, as of 
that of the mucous membrane, which forms some considerable 
longitudinal folds. This disposition belongs essentially to 
the nereides. 
In the amphitritae, including the pectinariae, the stomach 
is long, tolerably thick, but without any trace of ccecum. The 
same is the case w ith the terebellae. 
It does not appear that any distinct liver has yet been ob- 
served in the chetopoda, nor any organ which might per- 
form its lunctions, otherwise than some granulations in the 
thickness ol the intestine, as in the nereides, or which often 
terminate the cceca, and even form a projection under the 
skin ; such may be considered the small denticulated crests 
which are seen behind the root of the appendages in the 
