INTERNAL ANATOMY OF INSECTS. 123 



Let us now consider how the intestinal canal is cir- 

 cumstanced in the two sections into which the Class 

 AracJinida is divided ; the Scorpionidea, 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 occitanus 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. Diet. d'Hist. Nat. xxx. 423. Comp. Treviranus, Arachnid. 

 /.]./. 6. 



