THE MUSCLES. 



57 



Fig. 4. 



sertion. (Fig. 4.) 5. A single penniform muscle, like a quill with the 

 feathers stripped off one side, the quill part representing the tendon, 



Fig. 5. 



and the feathery part the oblique short muscular fibres. (Fig. 5) 

 6. A double penniform muscle, like the quill with both its rows of 

 feathers. 



Fig. 6. 



The number of muscles in the body is upwards of four hundred, 

 varying slightly in different individuals. They are arranged in four 



Fig. 7. 



