130 GENERAL BIOLOGY 



riorly through the foot. Here it turns on itself and extends 

 anteriorly again, then dorsally, passes through the ventricle 

 of the heart, goes dorsal to the posterior adductor muscle, 

 and ends at the anus in the cloacal chamber. 



5. The Reproductive Organs. The ovaries, or testes, are 

 present in the visceral mass .of the body. They are usually 

 light brown in color and entirely fill the spaces between the 

 folds of the intestine. The ducts empty near those of the 

 kidney in the supra-branchial chamber. 



Make a large drawing to show all the organs studied. 

 6. Sections of the Body. In order to show the relations 

 of the various organs of the body in a manner as clear as 

 possible a study of sections of the body is desirable. These 

 are sections across the entire body at different regions. 

 Make drawings of the sections and show the position and 

 arrangement of the organs that are in the section. Show the 

 plan of the organs by making the drawings rather diagram- 

 matic. 



(a) Section through the stomach, shows the stomach, 

 mantle, palps, liver, reproductive organs, anterior aorta, foot. 



(6) Section through the heart. Mantle folds, gills, supra- 

 branchial chamber, intestine (cut across several times), 

 pericardial cavity, ventricle, auricles, vena cava (a large vein 

 in the center of the body below the pericardial cavity), 

 kidney, ureters, reproductive organs. 



(c) Section through the posterior adductor muscle. Ad- 

 ductor muscle, intestine, gills, supra-branchial cavities, mantle, 



visceral ganglia of the nervous system. 







m. Physiology. 



1. Sensitiveness. Place a clam in a dish of water and 

 allow it to remain until the shell opens and the foot and 



