210 VERTEBRATES 



(4) Remove a nerve and dissect it as in the bird. See 

 page 189.) Find the parts and make a diagrammatic sketch 

 of a section running from cornea back through the optic 

 nerve. 



IV. The Head. — (i) Under the lower jaw find im- 

 bedded in the muscles the salivary glands, pink, roundish 

 bodies. Find four pairs, the parotid, the largest, just under 

 the ears ; the submaxillary, just in front of the parotid ; 

 the infra orbital, just below and in front of the eyes; and 

 the. sublingual, under the tongue near the meeting of the 

 bones of the lower jaw. Of what value are the salivary 

 glands? Find their ducts leading to the mouth. Care- 

 fully remove the tongue. Note its connection with the 

 esophagus. At the base of the tongue find the triangular 

 bone, the hyoid, embedded in the muscles. Was it at- 

 tached to any other bone? Of what use is the hyoid? 

 Study the tongue. Note the muscular base, the furred 

 surface and the shape. Has the surface the same appear- 

 ance in different parts? Explain. Examine the surface 

 for evidences of taste bulbs, or papillae. A section of a por- 

 tion of top of tongue would perhaps show this latter. Draw 

 surface of tongue. Of what value to the rabbit is the 

 tongue ? 



(2) Remove the muscles from the jaws. Note their 

 thickness and mode of attachment. Explain the advantages 

 of such form and arrangement. 



(3) Remove the lower jaw. Notice especially the nerVes 

 which run into the jaw from the head. Find tube leading 

 from the mouth into the ear, the Eustachian tube. Note the 

 opening from the nasal passage into the mouth, the pharynx. 

 Notice the teeth of the upper and lower jaws. How many 



