ALIMENTARY CANAL. 93 



Alimentary canal. From a point, either 

 just outside (Ectoprocta), or just within 

 (Entoprocta), the tentacle stage, there arises 

 another tubular extension of the funnel, or 

 body-wall, pendant and parallel with the other 

 tube. This corresponds with the intestine 

 and stomach, and united to the other tube at 

 the supposed free ends, forms with it the 

 complete alimentary canal, commencing with 

 a mouth and terminating in an anus. 



Tentacle stage circular. The 



alimentary canal is therefore suspended like a 

 loop from the bottom of the funnel, or anterior 

 end of body. In the great majority of the 

 Polyzoa, the tentacles are arranged in a circle 

 around the mouth (Holobranchia), but in some, 

 mostly from fresh water, the circle is not 

 complete, but side arms are thrown out, the 

 tentacle stage then taking the form of a 

 horse-shoe with the ends more or less 

 prolonged (Pterobranchia). 



Body cavity. Between the body-wall 

 and the alimentary canal is a space called the 

 body cavity. This is filled with a transparent 



