EXPLANATION OF THE PLATES. 



PLATE I. 



Half-grown nierlusa. 

 Full-grown medusa. 

 Side view of tentacle showing ectodermal 



ocellus. 

 Side view of manubrium showing nematocyst 



knobs. 

 Enlarged view of a nematocyst knob of 



manubrium. 

 Section of swollen portion of radial canal 



showing vacuolated eiitodermal cells. 

 Mature medusa. 

 Mature medusa. 



PLATE II. 



15a. 



" 15b, 15c. 



Mature medusa. 

 Mature medusa. 

 Mature medusa. 



Jlature medusa. 



Section of the manubrium showing medusa 

 buds, in various stages, developing within 

 the ectoderm (ect). The entoderm, and 

 the limiting membrane (s I) remaining 

 unbroken and inert 



Very young bud {ent. h), entoderm of the 

 bud. (c) Mass of cells within the central 

 cavity of the entoderm. These probably 

 contribute to the nutrition of the bud. 



Successive stages in the development of the 

 medusa buds. Lettering as in previous 

 figures. 



