ARTICULATA. 445 



to absorb the peculiar juices they are to produce, from the 

 mass of the nutritive fluid(l). 



Insects vary infinitely as to the form of the organs of the 

 mouth, and those of digestion, as well as in their industry and 

 mode of life ; the sexes are always separated. 



The Crustacea and Arachnides were long united with the 

 Insecta under one common name, and resemble them in many 

 points of their external form, in the disposition of their or- 

 gans of motion, and of the sensations, and even in those of 

 manducation. 



(1) On this subject see my Memoir on the nutrition of Insects, printed 1799, 

 Mem. dela Soc. d'Hist. Nat.de Paris. Baudouin, an vii, 4to, p. 32. 



