PLATE 2 



EXPLANATION OF FIGURES 



7 Sagittal section of specimen with mouth open. The enteric epithelium of 

 anterior sac and of floor of 'stomach' is everted at E.K. to form a sort of piston 

 within the lumen of partly distended pharynx. At fixation specimen ruptured 

 along fission plane (F). and 0', oocytes of two zooids. X 75. 



8 Hydra that had been half ingested from aboral end. During ingestion 

 polyp had contour A. When egested Hydra could distend and move oral half, 

 but aboral half of body was paralyzed. The polyp, with paralyzed aboral half, 

 had contour B. X 50. 



9 Part of pharyngeal epithelium (Ep) with gland-cells. A, young gland- 

 cell; B, gland-cell at maximum secretion phase; C, emply gland-cell; D, ducts of 

 gland-cells passing through lining epithelium of pharynx. X 1500. 



10 Frontal section of two zooids. Parent enteron completely divided, but 

 'brain' of posterior zooid yet lies in intimate contact with the enteron of anterior 

 zooid. Br, 'brain' of posterior zooid; E, enteron of anterior zooid. X about 

 100. 



320 



