50 ELEMENTARY BIOLOGY. [CHAP. 



immediately under cover of a small muscle {con- 

 strictor laryngis). 



c. Examine the above-named muscles. 



a. The geniohyoid; a band of tissue arising from 

 the body and cornu of the hyoid and passing 

 forwards to be inserted into the lower jaw. 



yS. The hyoglossus ; arising from the posterior cornu 

 and passing forwards in the middle line be- 

 neath a. to enter the substance of the tongue. 



y. The sterno-hyoid ; its cut end will be seen passing 

 up from behind to be attached along the outer 

 border of the body and cornu of the hyoid. 



8. The omohyoid ; its cut end will probably be 

 found attached to the outer anterior border of 

 the body of the hyoid (it arises from the shoulder 

 girdle). 



c. The petrohyoides ; a series of small slips lying 

 immediately beneath h. and passing between 

 the hyoid and hind region of the skull. 



3. Remove the ventral face of the right lung, and ex- 

 amine its interior under a hand lens. 



a. The lung sac ; thin-walled and distensible; highly 

 vascular and thickened around the larger vessels 

 which ramify within it. 



b. The bronchi; short membranous tubes placing 

 the lungs in communication with the laryngo- 

 tracheal cavity. 



4. Remove the respiratory organs together with the 

 floor of the mouth, and pin the whole down on its 

 side, left lung uppermost. Dissect away the floor of 



