VERTEBEATA. 85 



red, lobed organ with the heart located anteriorly 

 between two of its lobes. 



1. The Liver. 



a. Observe its size as compared with the heart. 



h. How many lobes are there ? 



c. Is it firm in texture ? 



d. Identify the bile sac, a small greenish sac lying 



underneath, between two of the lobes of the 

 liver. 



2. The Heart. 



a. What is its shape ? 



h. Observe its division into two auricles (the ante- 

 rior portion) and a ventricle (the posterior 

 conical portion). 



c. In a split heart observe the difference in the 



thickness of the walls of the auricles and ven- 

 tricle. Which is the thicker ? 



d. Observe an artery (arterial trunk) arising from 



the ventricle and passing forward over the 

 auricles. It divides to the right and left into 

 two branches, while each of these subdivides 

 into three smaller branches called arches. 



3. Draw the liver, and the heart with its arteries. 



J. The Alimentary Caual, Etc. 



1. Identify the four parts into which the alimentary 

 canal is divided in the body cavity. 

 a. The (esophagus, the short, wide, anterior portion 



leading from the mouth to the stomach. 

 h. The stomach. (The oesophagus and the stomach 

 together form the wide anterior portion of the 

 canal.) 

 c. The small intestine, the slender coiled part. 



