150 



CCELENTERA. 



into the general cavity ; but also because a number of parti- 

 tions or mesenteries extend from the body wall towards this 

 gullet. Some of the partitions are " complete," i.e., they 

 reach the gullet ; others are " incomplete," i.e., do not extend 

 so far inwards. The complete mesenteries are attached to 

 the oral disc above, to the side of the gullet, and to the base, 

 and all the mesenteries are ingrowths of the body wall. The 

 cavity of the anemone is thus divided into a number (some 



FIG. 46. Structure of Sea anemone. (After ANDRES.) 



t, Tentacles ; 0, mouth ; ces, oesophagus ; c, c', apertures through 

 a mesentery ; a, a', acontia ; g; genital organs on mesentery; m.f., 

 mesenteric filaments ; ;/z./., longitudinal muscles ; s, primary septum 

 or mesentery ; s', secondary septum; s", tertiary septum ; v, base of 

 gut cavity. 



multiple of six) of radial chambers. These are in com- 

 munication at the base, so that food particles from the gullet 

 may pass into any of the chambers between the partitions. 

 Moreover, each partition is perforated, not far from the 

 mouth, by a pore, besides which there is often another nearer 



