but lying dorsal to the pharynx. Note the nerves given off from 



the brain and also from the connectives on the sides of the pharynx. 



Make a diagram to show the reproductive and nervous systems. 



VI. BODY WALL. 



Pin out part of the body wall quite flat and note that the muscular 

 layer of the wall is interrupted along four longitudinal lines in which 

 are the setae in sacs or setigerous glands ; four of these occur in each 

 somite. Between somites 12 and 13 some of these glands are con- 

 spicuously large ; tease out one and note under the microscope the 

 color, shape and hardness of the setae. 



C. ANATOMY AND PHYSIOLOGY OF LIVING SPECI- 

 MENS. 



I. MOVEMENTS. 



1. Place a worm upon moist filter paper and observe the direc- 

 tion and method of movements. 



2. In small light-colored worms note the contraction of the 

 dorsal blood vessel and the movements of the blood toward the an- 

 terior. 



3. Gently touch different parts of the body and note which are 

 the most sensitive. 



4. Place the worm under a glass vessel with some cotton satur- 

 ated with chloroform, the vapor of which will render the animal 

 insensible ; when motion has ceased remove the worm and cut it 

 open as in the specimen previously dissected, but only in the anterior 

 region and a little to one side of the median line. Keep the specimen 

 wet with physiological salt solution. 



II. VASCULAR SYSTEM. 



If the specimen is not quite dead observe: 



a. The contraction of the hearts, dorsal vessel, and sub-neural 

 vessel ; in the latter the wave of contraction passes backward. 



b. Small blood vessels passing from the dorsal vessel to the 

 digestive tract, and from the ventral vessel to the body wall and to 

 the septa. 



c. Fine vessels seen upon the septa, body walls and the nephridia. 



III. COELOMIC FLUID. 



Puncture the body where not yet opened and take out in a fine 

 pipette some of the fluid of the body cavity, examine under a high 

 power and note :- 



i. \Yhite amoeboid corpuscles. 



43 



