84 Practical Zoology. 



spoonful of ether in a fruit jar nearly full of water, immerse the 

 frog in it, and cap the jar. 



1. Has the frog a neck? Find the division between the head 

 and the body by bending the parts and feeling for the joint. 



2. Back of and below each eye is an oval area, the membrane 

 of the eardrum, or tympanum. 



3. The fore limb consists of the arm, forearm, and hand. 



4. The hind limb consists of the thigh, leg, and foot. 



5. Count the fingers and toes. 



6. What differences are there between the fore and hind limbs? 



7. Open the mouth, seize the tongue with the forceps and draw 

 it forward ; observe that it is attached in front, but free behind. 

 How is such a tongue used ? 



8. Look closely for teeth. Where are they? 



9. Pass a bristle tipped with sealing wax into one of the nostrils. 

 Where does it enter the mouth ? 



10. Make a small opening in one of the tympanic membranes, 

 pass a bristle through this opening, and look for its appearance in 

 the mouth. The opening through which it appears is the Eusta- 

 chian tube. 



11. The mouth narrows back into the gullet. 



12. In the back part of the floor of the mouth is a small slit, 

 the glottis, leading to the lungs. 



13. Compare the colors and markings of the upper and lower 

 surfaces of the frog ; draw dorsal and ventral views of the dead 

 specimen, naming all visible parts. 



Use Jordan's Manual of the Vertebrates for finding the names of 

 any amphibians. 



DISSECTION OF A FROG 



i . Lay the frog on its back in a dissecting pan. Stretch out the 

 fore limbs close to one end of the board and tack to the board 

 through the hands ; then stretch the hind limbs well back and out 

 and tack the feet so the body will be firmly held. Common carpet 

 tacks can be set firmly enough by pressing with the thumb, and 

 will not need hammering. With forceps pinch up a fold of skii 



