VERMES. 39 



Phylum I. VERMES. Worms. 



Bilateral forms with unsegmented or segmented body, paired excretory 

 organs, dermal musculature, &c. A sharp diagnosis of this group is the less 

 easy, since it not only contains the most different forms, but also con- 

 necting links with all the higher phyla. The lower worms (Turbellaria) 

 similarly c.onnect themselves with the Ccelenterata (Ctenophora). 



The group of Vermes has long been made a receptacle for all sorts of doubt- 

 ful forms, and, since the removal of the Tunicata from the Molluscoidea, the 

 Polyzoa and Brachiopoda have usually been added to it. Ray Lankester 

 abandons both Vermes and Molluscoidea, and places their classes in separate 

 phyla. 



(1.) Platyhelmia. (Leeches are included here as well as ordinary flat- 

 worms. ) 



(2.) ISTematoidea (including Nematoda and Chsetognatha). 



(3.) Acanthocephala. 



(4.) Gastrotricha. 



(5.) Podaxonia (Gephyrea + Polyzoa + Brachiopoda). 



(6.) Appendiculata, seep. 62. TB. 



