CNIDARIA 



63 



cyst, and both fundaments at first have ahnost the same appearance. 

 In the further course of development, however, the fundament of the 

 nectocalyx protrudes out over the surface of the larva, and is constricted 

 off from it like a bud, whereas the pneumatophore remains sunk in the 





^— A 



Fig. 26.— Three stages of development of Agalma Sarsii (after Metschnikopf). 

 A, first fundament of the cap-shaped hydrophyllium on the ciliated larva ; i?, ab- 

 striciion of this fundament and development of the pneumatophore; C, stage witli 

 fundaments of three hydrophillia. d, primary cap-shaped hydrophillium ; (U, d^, 

 first and second heteromorphous hydrophillia; ec, ectoderm; en, entoderm; /, bud 

 of tentacle; g, mesoglcea; gv, gastrovascular cavity; p, fundament of pneumato- 

 phore; s, nutritive cells. 



apical end. A further difference from H. pictum results from the 

 eccentric position of the gastrovascular cavity, which is crowded quite 



