CNIDARIA 



63 



cyst, and both fundaments at first have almost 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 



en. 



^.,!(jj:^^s^. 



CC- 



W 



B 





V 



Fig. 26.— Three stages of development of AqoXma Sarsii (after Mktschnikoff). 

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

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

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

 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 



