56 



COELENTERATA 



absorptive cells in the gastrovascular endoderm, and secretory cells 

 which are small gland cells. 



Flacjellum 



—ip if —Pseudopoc/ium 



Fig. ^iA. Hydra, longitudinal section. (Modified from Parker. Courtesy of The 



Macmillan Co.) 



Nerve cells are present in hydra in the ectoderm, a few in the 

 endoderm. Some nerve cells are connected by processes with the 

 muscle fibers of the epitheliomuscular cells. 



