122 INTERNAL ANATOMY OF INSECTS. 



very different sentiments with regard to the structure of 

 the alimentary organs of the Class we are now to enter 

 upon, the Arachnida : what some regard as a real liver, 

 others look upon as an epiploon or caul ; and what the 

 last denominate bile-vessels are by some of the former 

 considered as appropriated to the secretion of chyle a . 

 Yet both these opinions have some foundation in nature. 

 When, in the Arachnida, we discover a lobular substance 

 consisting of granules filling the whole cavity of the body 

 and wrapped round the intestines, every one will see in 

 it no small analogy to the epiploon which in insects per- 

 forms the same function : but when, upon a further exa- 

 mination, we detect certain vessels communicating with 

 this substance and the intestinal canal b , the idea that 

 these may be hepatic ducts, and this substance analogous 

 to the liver, immediately strikes us as not improbable. 

 Again : when we discover pairs of other capillary and 

 tortuous vessels connecting with the intestinal canal either 

 at the pylorus c or below it d , which in appearance strik- 

 ingly resemble the bile-vessels which we so constantly 

 find in insects, we seem warranted in concluding that they 

 are of the same nature and use : but when a nearer in- 

 spection enables us to detect the hepatic ducts just men- 

 tioned in the scorpion, and we find that these capillary 

 vessels in the spider are in a very different situation from 

 those in insects which we suppose them to represent, it 

 occurs to us as not unlikely, that \he\rfunction may be 

 different. 



a Treviranus and Ramdohr are of the former opinion; and Meckel, 

 Cuvier, Marcel de Serres, and Leon du Four, of the latter. 

 b Treviran Arachnid, t, I./. 6. v. c Ibid, n. 



d Ibid. t. \\,f. 24. /3. 



