436 



MOLLUSCA : BRYOZOA. 

 FIG. 666. 



Fresh-water Polyzoa or Bryozoa, natural size, and magnified. 

 1-6, Plumatella arethusa, Hyatt ; 11-14, P. diffu.su,, Hyatt. (From Observations on 

 Polyzoa, by Alpheus Hyatt.) 



