Plate 24. 



Stages in the development of the parasitic generation of Pegantha smaragdina, sp. nov. 



Fig. 1. Longitudinal section of a larva, just prior to formation of gastric cavity. X 900. 



Fig. 2. Longitudinal section of a larva in which the gastric cavity (g.cav) is formed, but in 

 which the mouth has not yet broken through. The greater bulk of the larva 

 forms the primary tentacle; and the endodermic core (en.r) of a second tentacle 

 can be distinguished. X 900. 



Fig. 3. Somewhat diagrammatic longitudinal section of a larva in which the mouth is 

 opened, showing the earliest stage in budding at the aboral pole ; (en.r) endo- 

 dermic core of tentacle. X 300. 



Fig. 4. Surface view of the stage represented in figure 1. The main body of the larva is 

 probably the future primary tentacle. X 300. 



Fig. 5. Somewhat diagrammatic longitudinal section through a larva with bud constricted 

 ofE from gastric cavity; (en.r) endodermic core of tentacle; (m) mouth. 

 Eeconstructed from three successive serial sections, x 300. 



Fig. 6. Diagrammatic longitudinal section through aboral region of a larva with two 

 buds. The distal bud has an open mouth and a rudimentary tentacle ; its cavity 

 is entirely constricted off from that of the proximal bud. The cavity of the latter 

 is still connected with the gastric cavity of the parent larva. X 400. 



Fig. 7. Medusa stage, radial section through margin in plane of otocyst ; (ot) otolith ; (g) 

 mesogloea ; (s.lam) stutzlamella ; (en.lam) vascular endoderm lamella ; (n.r) 

 nerve ring ; (v) velum. X 500, 



Fig. 8. Similar section of a very early stage in the formation of the otocyst (ot). The 

 endodermic core of the otocyst is still continuous with the endodermic lamella 

 (en.lam). X 500. 



