148 ELEMENTS OF MAMMALIAN ANATOMY 



the camels the rumen and reticulum have connected with 

 them pouch-like diverticula for the storage of water. The 

 constricted openings of the pouches into the rumen or reticu- 

 lum may be entirely closed by sphincter muscles. 



In man and the higher apes there is present an attenuated 

 extension of the cecum known as the vermiform appendix. In 

 the fetus of man it is proportionally longer than in the adult. 

 In the herbivorous mammals, such as the cow and rabbit, 

 the cecum is greatly enlarged, so as to play an important 

 part in digestion. In a few forms, such as the sloths, some 

 Cetacea, and a few Carnivora, the cecum is absent. 



The lowest mammals, the Monotremata, resemble birds 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 thyreoid glands, pancreas, 

 and the liver are present in all mammals, but the gall-cyst is 

 absent in Cetacea, the Perissodactyla, Hyracoidea, and a few 

 Rodentia. The liver is usually relatively larger in fat-eating 

 animals. 



LABORATORY STUDIES 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. 



g. Name some mammals having only one set of teeth. 

 10. Give the dental formulae for three ungulates. 

 ir. 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. 



