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. 



10. Give the dental formulae 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. 



\yi6. 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? 



V 19. Make a section of a portion of the wall of the stomach and draw 

 what is seen, labelling all parts. 



V 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 

 ihe 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. 



