CHAPTER V. 



VERMES. 



Animals more or less, resembling in structure the 

 Earthworm (see p. 132). 



Classes. — Platyhelminihes, or Flat-worms. 



Nemathelmintees, or Round-worms. 

 Annelida, or Earthworm-like worms. 

 Sub-classes: ChjEtopoda, Gephtrea, 

 and Hietjdinea. 

 RoTATOElA, or Wheel-bearing animals. 



The VeKmes, or Worms, are the simplest kind of seg- 

 mented, animals (see p. 83). We have in this group 

 the beginnings of the segmented type. All are bi- 

 lateral : some of the lower forms are not segmented, 

 and those -that are segmented have the segments 

 much alike, instead of being variously modified for 

 different purposes. They have no legs. 



It should, however, be stated that the differences 

 between the lower and the higher worms are so im- 

 portant that some zoologists prefer to make the lowest 

 class {Platyhelminthes) a separate group, under the 

 name of Platodes. The group of Vermes is of great 

 importance as affording a sort of centre, from which 

 several other great groups seem to have branched oS. 

 This is indicated by the nature of their larval forms : 

 for some worms have a ciliated larval form called a 



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