MUSEUM OF COMPARATIVE ZOOLOGY. 285 



EXPLANATION OF THE PLATES. 



PLATE I. 



Fig. 1. Ocyroe crystallina (young). 



" 2. The same, with oral lobes expanded. 



" 3. A single oral lobe extended. 



" 4. Position assumed by the oral lobe. 



" 5. View of oral lobe from the aboral pole (expanded). 



" 6. The same contracted. 



" 7. Cassiopea frondosa in natural position. 



" 8. Young of the same (aboral view). 



" 9 a. Side view of young Cassiopea. 



" 9 b. Older larva of the same. 



" 10. Cassiopea frondosa (aboral view). 



" 11. The same (oral view). 



" 12. Marginal sense body of the same (aboral side). 



" 13. The same (oral side). 



" 14. Double marginal sense body of C. frondosa (monstrosity). 



" 15. The same (aboral view). 



" 16. Marginal sense body with two ocelli (monstrosity). 



" 17. Extremity of the oral arms of Cassio2)ea. 



" 18. Mouths and pouches of the same. 



" 19. Oral appendage from upper side. 



