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 Z>/fe-vesseIs 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 pglortis 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 their function may be 
different. 
a Treviranus and Ranulohr are cf the former opinion 3 and Meckel, 
Cuvier, Marcel de Serres, and Leon dn Four, of the latter. 
b Treviran Arachnid, t. ]./. (.», v. c Ibid. n. 
« Ibid. I. ii.y. 24. /?. 
