CNIDARIA 



63 



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

 In the fm-ther 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 



>:^jii0m^^ J- 



B fk 



PiG. 26. — Three stages of development of Agahna Sarsti (after Metschnikopf). 

 A, first fundament of the cap-shaped hjdrophyllium on the ciliated larva ; B, ab- 

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

 fundaments of three hydrophillia. d, primary cap-shaped hydrophillium ; d', ir, 

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

 of tentacle; g, mesogloea; 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 



