BUGULA 71 



Exercise 2. Draw an extended individual in which the entire digestive 

 tract can be seen and label all the organs observed. 



There are no special respiratory or excretory organs ; the entire 

 outer surface of the body performs these functions. The circu- 

 latory system is represented by the colorless blood fluid alone. 

 There are no circulatory vessels, the blood being contained in the 

 body cavity. 



Avicularia and Ocecia. These are peculiar structures, found in 

 connection with the zocecia, which are morphologically equiva- 

 lent to distinct individuals. An avicularium is a small structure, 

 like a bird's head in shape (hence the name), which may be found 

 attached to the wall of some of the zocecia near the opening. It 

 has a movable lower jaw which can be opened and shut by two 

 sets of muscles. Its function is to seize and hold small animals. 

 These soon die in its grasp, and their disintegrated remains are 

 swept into the mouth by the ciHated tentacles. An ooecium is a 

 disklike structure which, in some parts of the colony, lies in front 

 of a zooecium. It serves as an egg capsule in which the embryo 

 develops. A single embryo will be found in each. 



Exercise 3. Find a zooecium with an avicularium attached and 

 draw them. 



Exercise 4. Find a zooecium with an ooecium attached and draw them. 



