31 



XII. The Characters of the Genera of the Class 

 Myriapoda, with Descriptions of some Species, 



MYRIAPODA. 



Character externus. 

 Caput antennis 2 : mandibulis 2: maxillis 4 confluentibus 



in labium inferius transformatis. 

 Corpus inulti-articulatuni ; segmentis omnibus pedigeris. 



Obs. Pedum paria 2 antica saepe in labia 2 auxiliaria trans- 

 formata. 



It is to the researches of Savigny that naturalists are in- 

 debted for a knowledge of the change of form in those 

 parts which always exist under various modifications, in 

 the mouths of such annulose animals as have jointed legs. 



The three anterior segments of the body of the Myria- 

 poda seem to correspond with the thorax of insects. This 

 idea was suggested to me by Blainville, Latreille, and Sa- 

 vigny, and has received a strong degree of probability from 

 the observations that I have since had an opportunity to 

 make. 



In Crustacea, Myriapoda, Arachnides, and Insecta, 

 the nervous system is very similar : as far as I have ob- 

 served, the first ganglion always receives nerves from the 

 parts proper to the head ; the three following ones, from 

 the three anterior pairs of legs and parts adjacent ; and the 

 rest, from the viscera of the abdomen and its appendices. 



Before the publication of Savigny "s IMemorial on the 

 Mouths of Insects, &c. naturalists had fallen into many 



