INTERNAL ANATOMY OF INSECTS. 123 
Let us now consider how the intestinal canal is cir- 
cumstanced in the two sections into which the Class 
Arachiida is divided ; the Sco?'pio7iidca, and Araneidea. 
In the Scorpions, this organ proceeds from the mouth 
to the anus without any flexure or convolution, so that 
its length is scarcely equal to that of the body a ; it is 
slender, and its diameter, with the exception of an irre- 
gular dilatation here and there, is nearly the same in 
its whole extent ; the gullet is short ; the stomach long, 
and nearly cylindrical; the duodenum shorter and thicker 
than the stomach, from which, as well as from the rectum, 
it is separated by a valve ; the latter is cylindrical, and 
opens at the anus above the insertion of the vesicle that 
secretes the poison b . With regard to the biliary system 
and its organs: The liver is of a pulpy granular consis- 
tence and of a brownish colour, fills the whole cavity of 
the trunk and abdomen, and serves as a bed for the other 
intestines. It is divided longitudinally into two portions, 
by the channel in which the heart reposes — its anterior 
part is formed into many irregular lobes, by the sinuosi- 
ties of the trunk ; at the other extremity, it terminates in 
two acute ends, which enter the first joint of the tail ; its 
surface presents a reticular appearance, the result of the 
approximation of polygonous lobuli; its interior is a tissue 
of infinitely minute glands : in Scorpio occitcums there are 
about forty pyramidal lobuli detached from each other, 
the summits of which, by their union, form bunches that 
have their excretory canals, varying in number in dif- 
ferent species, which convey the bile to the alimentary 
a Treviran Arachnid./. 6. B B. 
b N. Did. (VHist. Nat. xxx. 423—. Comp. TreviraBUS, Arachnid, 
t. If. G. 
