Plate 13. 



Poralia rufescens. 

 Fig. 1. Oral view of the best-preserved specimeu. Those portions of the margin which 



have been reconstructed are indicated by dotted outlines. Reduced one half. 

 Fig. 2. Oral view of a small segment of the gastric wall, with gonads (go) ; gastric illa- 



ments (g.f) and bases of canals (era). X 1.5. 

 Fig. 3. Portion of the gastric wall, viewed from within ; (g.os) gastric ostia (openings 



of the radial canals) ; (go) gonad ; (g) gelatinous substance of the disc. X 2. 

 Fig. 4. Rhopalium, aboral view; (p) exumbral sensory pit; (s) covering scale; (r) rho- 



palium. X 15. 

 Fig. 5. Dissection of margin with side view of sense organ ; (p) sensory pit, seen through 



a thin layer of the mesogloeauf (s) covering scale; (oc) otocyst at the tip of the 



rhopalium ; (r.c) rhopalar canal. X 30. 



