PLATE XIX. 



Fig. I. Campatiularia regia Nutting. Single hydrotheca, showing hjdranth 

 (much less enlarged than the other figures). 



2. Another hydrotheca, showing reduplication of margin. 



3. Hydrotheca of C. spectosa Clark (drawn to the same scale as fig. 1, to 

 show comparative size). 



4. Obelia borealis Nutting. Part of colony, showing hydrothecae and 

 gonangium (enlarged). 



5 and 6. Gonangia (greatly enlarged). 



(202) 



