PLATE II. 



Fi>'. 1- Larger kind of reproductive polypite of adiilt Velella : a, actinal opening ; b, clusters of lasso- 

 cells forming patches over the surface of the upper extremity of the polypite ; mm, clusters of 

 medusK buds in different stages of development, magnified. 



Fie -2. Actinal opening of feeding polypite. Fig. 4. 



Fig. 3. Another view of the actinal opening of a reproductive polypite. 



Fi». 4. Magnified view of larger feeding polypite ; in these the patches of lasso-cells are but slightly de- 

 veloped towards the free extremity ; near the base, however, they form huge spheres b'b', 

 studded in part with gigantic lasso-cells. 



Fie 5. Smaller kind of reproductive polypite, more slender than Fig. 1, with a smaller number of 

 medusie buds. The patches of lasso-cells are clustered together so as to form hemispherical 

 projections, which become slightly pedunculated towards the base. 



Fiw. 6. Mat'nitied view of two of the hemispherical clusters of lasso-cells of the surface of one of the 

 smaller proliferous polypites. These polypites are open at the extremity. 



Fig. 7. Another view of a smaller proliferous polypite distended with food. 



Fig. 8. Small and slender feeding polypite. Lettering as in Fig. 4. 



Fie. 9. Actinal extremity of one of the smaller kinds of feeding polvpites greatly extended. 



Fi". 10. Medusse of Velella freed twelve hours from the reproductive polypites : (/, digestive cavity ; 

 ch, chymiferous tubes ; i/, yellow cells ; I, one of the large lasso-cdls forming the four lines 

 runnincr from the tentacles to the apex ; ft', large and small rudimentary tentacle ; to, acti- 

 nostome. 



Fig. 11. Somewhat older than preceding stage. Lettering as above. 



Fif. 12. Fig. 10 seen from above with the sides of the bell slightly drawn in. 



Fie. 13. Young Velella just before it separates from the proliferous polypites. 



Fi^T. 14. Magnified view of the base of the rudimentary tentacular bulb: I, outer line of lasso-cells in the 

 periphery of the bell ; /, rudimentary tentacle ; g, clusters of yellow cells. 



Fif. 15. Medusa of Velella copied from drawings for L. Agassiz's Contributions to the Natural History 

 of the United States. 



Fig. 16. Same seen from the abactinal pole. 



