EAETHWOEM 129 



of it on a slide, put on the cover-glass, and ex- 

 amine with a low, then with a high power. Note 

 that the fluid consists of a watery part, the 

 serum, in which float numerous amoeboid cells, 

 the corpuscles, as well as various Protozoa^ small, 

 thread-like worms, fragments of tissue, etc. The 

 corpuscles may be stained with magenta or with 

 acetic acid carmine if desired. Does the peri- 

 visceral fluid coagulate when exposed to the air ? 

 Draw several of the cells and other bodies found. 



G. The mesenteric septa. — Position? Shape? What 

 is their relation to the constrictions between the 

 somites in different regions? What is their re- 

 lation to the alimentary canal? Why are they 

 called " mesenteric " ? What is their structure ? 



A. The Digestive System. 



What is its position in the body? General shape? 

 How do its parts lie with reference to one another? 

 Make out the following parts in order. 



The first two or three segments are occupied by 



a. The buccal cavity. — How formed ? Shape ? 

 How are its walls connected to the body-wall? 

 Does it contain any teeth ? How is it separated 

 from the pharynx ? 



h. The pharynx. — Shape ? Size ? Through what 

 segments does it extend? What is the nature 

 of its waU ? How is it held in place ? 



G. The cesophagus or gullet. — What is its shape? 

 Structure ? In what segments does it lie ? Is its 

 calibre the same throughout its entire length ? 

 In segments eleven and twelve look for 

 9 



