12 



GENERAL SURVEY OF THE ANIMAL KINGDOM 



ectoderm or epiblast, internal endoderni or hypoblast lining the gut, 

 and a median mesoderm or mesoblast lining the body cavity). In the 

 next two classes (Ccelentera and Sponges) the conditions are different, 

 as may be expressed in the following table : — 



Ccelentera. — This series includes jelly-fishes, sea- 

 anemones, corals, zoophytes, and the like, most of which are 



Fig. 1 6. — Sea-anemones on back of hermit-crab. 

 — After Andres. 



equipped with stinging cells, by means of which they 

 paralyse their prey. All but a few are marine. The body 

 may be a tubular polyp, or a more or less bell-like " medu- 



