PLATE 15. 



Fig. i. Lvmnorfa borealis. Eastport, Maine, September 19, 1898. 



Fig. 2. Lymnorea borealis. Side view ot the oral tentacles. 



Fig. }. Lvmnorfa borealis. View ot the nematocyst-capsules upon the oral 



tentacles. 

 Fig. 4. Lymnorea alexandn, young medusa. Nassau Harbor, Bahamas, 



June, 1903. 

 Fig. 5. Lymnorea alexandn, mature medusa. Nassau Harbor, Bahamas, 



July, 1903. 

 Fig. 6. Lvmnorea alexandri. Cross-section showing the gland-cells ot" the 



mid-region ot a radial-canal of the medusa shown in figure 5. 

 Fig. ". Lvmnorfa alexandrl. Knob-like end ot" one of the oral tentacles 



showing the nematocysts. 

 Fig. 8. Lvmnorea ale\anJri. Mouth parts ot" the young medusa shown in 



figure 4. 



Fig. 9. Lvmnorea ale\andrt. Marginal tentacle. 



Fig. 10. Turritopsis nutricula, young medusa. Agassiz Laboratory, New- 

 port, Rhode Island, August, 1892. 



Fig. ii. Turritopsis nutricula, young medusa. Newport, Rhode Island. 

 Fig. 12. Turritopsis nutricula. View ot the lips ot a mature male medusa. 



Tortugas, Florida, April 6, 1906. 

 Fig. 1 3. Turritopsis nutricula. Aboral view ot manubrium showing the 



vacuolated entodermal cells surrounding radial-canals. Tortugas, 



Florida, April n, 1906. 

 Fig. 14. Podocoryne carnea, mature female. Agassiz Laboratory, Newport, 



Rhode Island, July, 1895. 



Drawn trom lite, by the author. 



