ORGANS OF DIGESTION. 127 
and reptiles in possessing a cloaca into which open the 
rectum and the urinary and genital ducts. The cloaca 
opens externally through the anus. Salivary and thyroid 
glands, pancreas, and liver are present in all mammals, but 
the gall-cyst is absent in Cetacea, the Perissodactyla, Hyra- 
coidea, and a few Rodentia. The liver is usually relatively 
larger in fat-eating animals. 
PRACTICAL QUESTIONS AND SUGGESTIONS. 
1. Describe the fauces. 
2. Describe in detail every feature visible on the dorsal surface of 
*the tongue. 
3. Give the number of fangs in each tooth of the permanent set. 
4. Give the number of each kind of teeth in the two sets. 
5. Draw two aspects of the sectorial tooth. 
6. How thick is the enamel of the teeth? 
7. Name some mammals which do not have enamel on the teeth. 
8. Name some toothless mammals. 
9. Name some mammals having only one set of teeth. 
1o. Give the dental formule for three ungulates. 
11. In what animals are some of the teeth greatly enlarged? 
12. Do any ruminants have upper incisors? 
13. Name the important features of the pharynx. 
14. Name every organ in the abdominal cavity, telling with what 
other organs it is in contact. 
15. Describe as much of the peritoneum as you can see in your 
specimen. 
16. Draw the alimentary canal in its natural position, showing all 
ducts leading into it, and label all parts. 
17. How much longer is the small intestine than the large one? 
18. On what does the length of the canal in different mammals 
largely depend? 
19. Make a section of a portion of the wall of the stomach and draw 
what is seen, labelling all parts. 
20. Make a section of the small intestine, draw what can be seen by 
naked eye or simple microscope. 
21. About how many villi to each square millimeter? 
22. Describe the two channels through which the food passes from 
the intestines to the heart. 
23. Make a somewhat diagrammatic drawing representing that part 
of the venous system conveying the food from the intestines to the heart. 
