LECTURE IX. 93 



The celebrated Cuvier seems to suppose that they 

 have not. It is acknowledged indeed that the 

 animals of the Crab and Lobster tribe, the Mo- 

 noculi, and others of that particular cast, have a 

 genuine circulation; but these animals should, 

 according to some Zoologists, be separated from 

 insects, and form a distinct division in the animal 

 kingdom. Nay Monsieur Lamarck is willing to 

 exclude even the Spider tribe from the class of 

 insects, because in these animals the heart and 

 circulation of the blood are distinctly visible. 



The organ which the famous Italian anatomist 

 Malpighi supposed to constitute the heart, or 

 rather a kind of chain of hearts, in the Silkworm, 

 has been since proved to be a vessel of a different 

 nature, the use of which does not appear to be 

 fully understood; but no ramifications of blood- 

 vessels proceed from it. 



It seems to have escaped the attention of those 

 who are not willing to allow a circulation of the blood 

 in insects, that, though it may not be perceptible 

 in the major part, yet it certainly appears to take 

 place in some which are allowed on all hands to 

 be genuine insects; and particularly in the genus 

 Cimex or Bug. I shall here give a quotation on 



