168 



Aquatic Organisms 



extend their tips outward in graceful curves. Then one 

 sees a mouth in the midst of the tentacles, and water- 

 currents set up by the lashing of the cilia which cover 



FIG. 78. A colony of Pectinatella, one-half natural size. Note the 

 distribution of buds in close groups over the surface. The large 

 hole marks the location of the stick around which the colony grew. 



them. A close examination with the microscope will 

 reveal in each zooid the usual system of animal organs. 

 The alimentary canal is U-shaped its two openings 

 being near together at the exposed end of the body. 



