- -10 - HYDRA. 



73. Transverse Section. Examine the stained preparation under the high power 

 and make a drawing to show : body-wall and digestive cavity ; ectoderm, consisting of 

 musculo-epithelial cells with nuclei and vacuoles ; interstitial cells ; nematocysts, both 

 developing and fully formed ; mesogleu ; endoderm, consisting of granular secretory 

 cells and vacuolated nutritive cells, some of which contain food particles. 



73a. Demonstrations. 



(a) Whole animal expanded. 



(b) ,, ,, retracted and containing ]ood. 



(c) budding. 



(d) Transverse section through testis. 

 (c) ovary. 



