GENERAL ZOOLOGY 



Fig. 14.17. Class Archiannelida: development of Polyi^nrdnLs. A, trochophore larva. B, early 

 stage in the development of the segmented, wormlike body. C, intermediate stage. D, \oung 

 adult worm. Note the presence, in the early stages, of a protonephridial system which dis- 

 appears during the transformation to adulthood. The zone of growth lies just anterior to the 

 last segment. (Redrawn from B. Hatschek, Studien iiber Entwuklunosoeschichle der Anmlideru 

 Vienna, 1878.) 



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