Fig. 9. An atte.chea scyphistoma with rjoLiments of eight 

 tentacles. More usual form. 



Fig. 10. Scyphistoma with rudiments of the second set of 

 eight tentacles. 



Fig. 11. Scyphistoma with sixteen tentacles fully devel- 

 oped. 



Fig. 12. Oral aspect of a similar specimen. 



Fig. 13. Scj-phistoma showing first traces of rhopalial 

 structures. 



Fig. 14. Scyphistoma at a slightly older stage. 



Fig. 14a. Small part of the margin of a similar larva. 



Fig. 15. An early stage in strobilization. 



Fig. 15a. A rhopalial tentacle of the same specimen seen 

 from the side. 



Fig. 16. An older rhopalial tentacle. 



Fig. 17. Strobila in which the rhopalial tentacles have 

 begun to degenerate. 



Fig. 18. One in which the interrhopalial tentacles have 

 also begun to degenerate. 



Fig. 19. A complete Strobila. 



Fig. 20. The basal segment remaining after strobilization 



Fig. 21. An Ephyrula recently set free. 



Fig. 22. A specimen of about the same age showing varia- 



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