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XXXI. A tabular View of the external Characters of Four Classes 
of Animals, which Linni arranged under Insecta; with the 
Distribution of the Genera composing Three of these Classes into 
Orders, ^c. and Descriptions of several New Genera and Species. 
By William Elf ord Leach, M.D. 
Read April 19» May 3, and June 1, 1814. 
The object of this paper is chiefly to call the attention of 4 
Entomologists to examine into the propriety of constituting 
a new class to comprehend the Syngnatha and Chilognatha of 
Fabi’icius, which Latreille and Lamarck have arranged with the 
Arachnides. 
As the leading characters of the classes which were considered 
by Linne as Insecta are very obvious, I shall in the first place 
content myself with submitting to the Society the external cha- 
racters, through the medium of a table, and shall then considti 
three of the classes separately. 
All the animals in question agree in having articulated limbs 
for motion, and they all have their spinal mass of nerves com- 
posed of ganglia, which are formed as it were on a cord ; or, in 
other words, are brought into communication with each other. 
By the following table the most obvious points of distinction 
may readily be learnt. 
A. Bran- 
