4 ELEMENTS OF MAMMALIAN ANATOMY. 



masseter muscle; (2) the angle which is the caudo ventral 

 termination of the bone; (3) the inferior notch imme- 

 diately dorsal of the angle; (4) the condyle for the articu- 

 lation with the glenoid cavity of the temporal; (5) the 

 superior notch dorsal of the condyle; (6) the coronoid 

 process, which is the dorsal termination of the ascending 

 ramus and gives insertion to the temporal muscle. 



THE HYOID BONES OR HYOID APPARATUS. 



The hyoid bones consist of two jointed rods, one on 

 either side (Figs. 20 and 21), hanging from the temporal 

 bone, and supporting the larynx. Each rod is composed of 

 six parts : the epihyal; the ceratohyal; the tympanohyal; the 

 basihyal; and the thyrohyal. The dorsal end of the thyro- 

 hyal is prolonged by a piece of cartilage, the chondrohyal. 



The hyoid apparatus varies greatly among mammals. 

 In man it consists of a single bone composed of the body 

 or basihyal, two small cornua representing the ceratohyals, 

 and two large cornua representing the thyrohyals. The 

 bone is suspended from the skull by ligaments correspond- 

 ing to the bony chain in the cat. 



'PRACTICAL QUESTIONS AND SUGGESTIONS. 



1. How many more bones are present in the cat than in man? 



2. In what two parts of the skeleton does the number of bones in 

 the cat exceed those in man? 



3. What is a sesamoid bone? 



4. Find on a specimen a sesamoid bone and describe it. 

 /5. Draw a lateral aspect of the skull and label all parts. 



6. What are the paired bones of the cranium? 



7. Name the single bones of the face. 



*^. Draw the caudal aspect of the skull and label all parts. 

 9. Which bones of the skull derive their names from their location? 



10. Which bones of the skull are pierced by more than two foramina? 



11. Write a description of the orbital cavity. 



12. Which foramina of the skull derive their names from their shape 

 or size? 



