256 SUPPLEMENT 



cardia alone is very apparent by the difference of volume in 

 the oesophagus. Two blind vessels, rather short and thick, 

 which lead to the stomach, have been considered by some 

 naturalists as cceca, and by others as replacing the liver. 



From the end of the stomach, the intestinal canal proceeds 

 pretty directly to the anus. Its diameter is then nearly equal 

 throughout, and sometimes very inconsiderable. Sometimes, 

 towards the middle, it presents a sort of swelling within, 

 which is a strong valvule, and from it proceeds a very long 

 coecum, as in the decapods. Sometimes, as in the entomo- 

 straca, there is no trace of these parts. Finally, its termina- 

 tion is always situated on the lower face of the last segment 

 of the tail or abdomen. 



The liver in the crabs, astaci, and other decapod Crustacea, 

 is a very voluminous organ, especially at certain periods of the 

 year. It is situated at the lower face of the body, that is to 

 say, underneath the stomach, heart, and preparatory organs of 

 generation ; and in the paguri it fills up more than the entire 

 base of the tail. Its general form is indeterminate, for it is not 

 comprised in a proper membranaceous envelope, such as the 

 conglomerate glands of vertebrated animals possess. It is 

 composed of an innumerable multitude of small secretory sacs, 

 intermingled together, of a yellow colour, whose parietes ap- 

 pear spongy, and which contain a brown and bitter humour, 

 which is the bile. Their communication with the intestinal 

 canal by hepatic ducts has not been yet pointed out ; but 

 there is reason to believe that it exists not far from the sto- 

 mach, if it be not in the stomach itself. 



In the Squilla?, the liver, solid, and very similar to a con- 

 glomerate gland, is divided into lobes, and these lobes are 

 ranged on the two sides of the whole length of the intestinal 

 canal. In the limulEe, the liver pours the bile into the intes- ' 

 tine, through two canals on each side. In oniscus we merely 

 remark, close by the oesophagus, four voluminous and blind 



