CH^TOGNATHA 45 



This branch presents similarities to both Platyhelminthes 

 and Annulata, but the relationship with either is not close. 

 Classification. 



Class. Examples. 



I. Nemato'da. Trichina, Gordius. 



II. Acan'thoceph'ala. 1 Echinorhynchus. 



III. Chaetog'natha. 1 Sagitta. 



'"The affinities of the Acanthocephala and Chsetognatha with the 

 Nematoda are somewhat doubtful," Parker and HaswelPs "Zoology," vol. 

 i, p. 275. 



