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 

 coeca 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 parietes 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 pectinaria), the stomach 

 is long, tolerably thick, but without any trace of coecum. The 

 same is the case with the terebella). 



It does not appear that any distinct liver has yet been ob- 

 served in the chetopoda, nor any organ which might per- 

 form its functions, otherwise than some granulations in the 

 thickness of the intestine, as in the nereides, or which often 

 terminate the coeca, and even form a projection under the 

 skin ; such may be considered the small denticulated crests 

 which are seen behind the i-oot of the appendages in the 



